Sync with the latest Gnulib code 668c0b8ffa

187 files changed, 12551 insertions, 4870 deletions

diff --git a/gl/m4/00gnulib.m4 b/gl/m4/00gnulib.m4
index d4ad759f..7fe03e0b 100644
--- a/gl/m4/00gnulib.m4
+++ b/gl/m4/00gnulib.m4
@@ -1,27 +1,82 @@
-# 00gnulib.m4 serial 2
-dnl Copyright (C) 2009-2013 Free Software Foundation, Inc.
+# 00gnulib.m4 serial 8
+dnl Copyright (C) 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl This file must be named something that sorts before all other
-dnl gnulib-provided .m4 files.  It is needed until such time as we can
-dnl assume Autoconf 2.64, with its improved AC_DEFUN_ONCE semantics.
+dnl gnulib-provided .m4 files.  It is needed until the clang fix has
+dnl been included in Autoconf.
 
-# AC_DEFUN_ONCE([NAME], VALUE)
-# ----------------------------
-# Define NAME to expand to VALUE on the first use (whether by direct
-# expansion, or by AC_REQUIRE), and to nothing on all subsequent uses.
-# Avoid bugs in AC_REQUIRE in Autoconf 2.63 and earlier.  This
-# definition is slower than the version in Autoconf 2.64, because it
-# can only use interfaces that existed since 2.59; but it achieves the
-# same effect.  Quoting is necessary to avoid confusing Automake.
-m4_version_prereq([2.63.263], [],
-[m4_define([AC][_DEFUN_ONCE],
-  [AC][_DEFUN([$1],
-    [AC_REQUIRE([_gl_DEFUN_ONCE([$1])],
-      [m4_indir([_gl_DEFUN_ONCE([$1])])])])]dnl
-[AC][_DEFUN([_gl_DEFUN_ONCE([$1])], [$2])])])
+# The following definitions arrange to use a compiler option
+# -Werror=implicit-function-declaration in AC_CHECK_DECL, when the
+# compiler is clang.  Without it, clang implicitly declares "known"
+# library functions in C mode, but not in C++ mode, which would cause
+# Gnulib to omit a declaration and thus later produce an error in C++
+# mode.  As of clang 9.0, these "known" functions are identified through
+# LIBBUILTIN invocations in the LLVM source file
+# llvm/tools/clang/include/clang/Basic/Builtins.def.
+# It's not possible to AC_REQUIRE the extra tests from AC_CHECK_DECL,
+# because AC_CHECK_DECL, like other Autoconf built-ins, is not supposed
+# to AC_REQUIRE anything: some configure.ac files have their first
+# AC_CHECK_DECL executed conditionally.  Therefore append the extra tests
+# to AC_PROG_CC.
+AC_DEFUN([gl_COMPILER_CLANG],
+[
+dnl AC_REQUIRE([AC_PROG_CC])
+  AC_CACHE_CHECK([whether the compiler is clang],
+    [gl_cv_compiler_clang],
+    [dnl Use _AC_COMPILE_IFELSE instead of AC_EGREP_CPP, to avoid error
+     dnl "circular dependency of AC_LANG_COMPILER(C)" if AC_PROG_CC has
+     dnl not yet been invoked.
+     _AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM([[
+           #ifdef __clang__
+           barfbarf
+           #endif
+           ]],[[]])
+        ],
+        [gl_cv_compiler_clang=no],
+        [gl_cv_compiler_clang=yes])
+    ])
+])
+AC_DEFUN([gl_COMPILER_PREPARE_CHECK_DECL],
+[
+dnl AC_REQUIRE([AC_PROG_CC])
+dnl AC_REQUIRE([gl_COMPILER_CLANG])
+  AC_CACHE_CHECK([for compiler option needed when checking for declarations],
+    [gl_cv_compiler_check_decl_option],
+    [if test $gl_cv_compiler_clang = yes; then
+       dnl Test whether the compiler supports the option
+       dnl '-Werror=implicit-function-declaration'.
+       save_ac_compile="$ac_compile"
+       ac_compile="$ac_compile -Werror=implicit-function-declaration"
+       dnl Use _AC_COMPILE_IFELSE instead of AC_COMPILE_IFELSE, to avoid a
+       dnl warning "AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS".
+       _AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]],[[]])],
+         [gl_cv_compiler_check_decl_option='-Werror=implicit-function-declaration'],
+         [gl_cv_compiler_check_decl_option=none])
+       ac_compile="$save_ac_compile"
+     else
+       gl_cv_compiler_check_decl_option=none
+     fi
+    ])
+  if test "x$gl_cv_compiler_check_decl_option" != xnone; then
+    ac_compile_for_check_decl="$ac_compile $gl_cv_compiler_check_decl_option"
+  else
+    ac_compile_for_check_decl="$ac_compile"
+  fi
+])
+dnl Redefine _AC_CHECK_DECL_BODY so that it references ac_compile_for_check_decl
+dnl instead of ac_compile.  If, for whatever reason, the override of AC_PROG_CC
+dnl in zzgnulib.m4 is inactive, use the original ac_compile.
+m4_define([_AC_CHECK_DECL_BODY],
+[  ac_save_ac_compile="$ac_compile"
+  if test -n "$ac_compile_for_check_decl"; then
+    ac_compile="$ac_compile_for_check_decl"
+  fi]
+m4_defn([_AC_CHECK_DECL_BODY])[  ac_compile="$ac_save_ac_compile"
+])
 
 # gl_00GNULIB
 # -----------
diff --git a/gl/m4/__inline.m4 b/gl/m4/__inline.m4
new file mode 100644
index 00000000..acf8668b
--- /dev/null
+++ b/gl/m4/__inline.m4
@@ -0,0 +1,22 @@
+# Test for __inline keyword
+dnl Copyright 2017-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl___INLINE],
+[
+  AC_CACHE_CHECK([whether the compiler supports the __inline keyword],
+    [gl_cv_c___inline],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+         [[typedef int foo_t;
+           static __inline foo_t foo (void) { return 0; }]],
+         [[return foo ();]])],
+       [gl_cv_c___inline=yes],
+       [gl_cv_c___inline=no])])
+  if test $gl_cv_c___inline = yes; then
+    AC_DEFINE([HAVE___INLINE], [1],
+      [Define to 1 if the compiler supports the keyword '__inline'.])
+  fi
+])
diff --git a/gl/m4/absolute-header.m4 b/gl/m4/absolute-header.m4
new file mode 100644
index 00000000..e7947648
--- /dev/null
+++ b/gl/m4/absolute-header.m4
@@ -0,0 +1,100 @@
+# absolute-header.m4 serial 17
+dnl Copyright (C) 2006-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Derek Price.
+
+# gl_ABSOLUTE_HEADER(HEADER1 HEADER2 ...)
+# ---------------------------------------
+# Find the absolute name of a header file, testing first if the header exists.
+# If the header were sys/inttypes.h, this macro would define
+# ABSOLUTE_SYS_INTTYPES_H to the '""' quoted absolute name of sys/inttypes.h
+# in config.h
+# (e.g. '#define ABSOLUTE_SYS_INTTYPES_H "///usr/include/sys/inttypes.h"').
+# The three "///" are to pacify Sun C 5.8, which otherwise would say
+# "warning: #include of /usr/include/... may be non-portable".
+# Use '""', not '<>', so that the /// cannot be confused with a C99 comment.
+# Note: This macro assumes that the header file is not empty after
+# preprocessing, i.e. it does not only define preprocessor macros but also
+# provides some type/enum definitions or function/variable declarations.
+AC_DEFUN([gl_ABSOLUTE_HEADER],
+[AC_REQUIRE([AC_CANONICAL_HOST])
+AC_LANG_PREPROC_REQUIRE()dnl
+m4_foreach_w([gl_HEADER_NAME], [$1],
+  [AS_VAR_PUSHDEF([gl_absolute_header],
+                  [gl_cv_absolute_]m4_defn([gl_HEADER_NAME]))dnl
+  AC_CACHE_CHECK([absolute name of <]m4_defn([gl_HEADER_NAME])[>],
+    [gl_absolute_header],
+    [AS_VAR_PUSHDEF([ac_header_exists],
+                    [ac_cv_header_]m4_defn([gl_HEADER_NAME]))dnl
+    AC_CHECK_HEADERS_ONCE(m4_defn([gl_HEADER_NAME]))dnl
+    if test AS_VAR_GET([ac_header_exists]) = yes; then
+      gl_ABSOLUTE_HEADER_ONE(m4_defn([gl_HEADER_NAME]))
+    fi
+    AS_VAR_POPDEF([ac_header_exists])dnl
+    ])dnl
+  AC_DEFINE_UNQUOTED(AS_TR_CPP([ABSOLUTE_]m4_defn([gl_HEADER_NAME])),
+                     ["AS_VAR_GET([gl_absolute_header])"],
+                     [Define this to an absolute name of <]m4_defn([gl_HEADER_NAME])[>.])
+  AS_VAR_POPDEF([gl_absolute_header])dnl
+])dnl
+])# gl_ABSOLUTE_HEADER
+
+# gl_ABSOLUTE_HEADER_ONE(HEADER)
+# ------------------------------
+# Like gl_ABSOLUTE_HEADER, except that:
+#   - it assumes that the header exists,
+#   - it uses the current CPPFLAGS,
+#   - it does not cache the result,
+#   - it is silent.
+AC_DEFUN([gl_ABSOLUTE_HEADER_ONE],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_LANG_CONFTEST([AC_LANG_SOURCE([[#include <]]m4_dquote([$1])[[>]])])
+  dnl AIX "xlc -E" and "cc -E" omit #line directives for header files
+  dnl that contain only a #include of other header files and no
+  dnl non-comment tokens of their own. This leads to a failure to
+  dnl detect the absolute name of <dirent.h>, <signal.h>, <poll.h>
+  dnl and others. The workaround is to force preservation of comments
+  dnl through option -C. This ensures all necessary #line directives
+  dnl are present. GCC supports option -C as well.
+  case "$host_os" in
+    aix*) gl_absname_cpp="$ac_cpp -C" ;;
+    *)    gl_absname_cpp="$ac_cpp" ;;
+  esac
+changequote(,)
+  case "$host_os" in
+    mingw*)
+      dnl For the sake of native Windows compilers (excluding gcc),
+      dnl treat backslash as a directory separator, like /.
+      dnl Actually, these compilers use a double-backslash as
+      dnl directory separator, inside the
+      dnl   # line "filename"
+      dnl directives.
+      gl_dirsep_regex='[/\\]'
+      ;;
+    *)
+      gl_dirsep_regex='\/'
+      ;;
+  esac
+  dnl A sed expression that turns a string into a basic regular
+  dnl expression, for use within "/.../".
+  gl_make_literal_regex_sed='s,[]$^\\.*/[],\\&,g'
+  gl_header_literal_regex=`echo '$1' \
+                           | sed -e "$gl_make_literal_regex_sed"`
+  gl_absolute_header_sed="/${gl_dirsep_regex}${gl_header_literal_regex}/"'{
+      s/.*"\(.*'"${gl_dirsep_regex}${gl_header_literal_regex}"'\)".*/\1/
+      s|^/[^/]|//&|
+      p
+      q
+    }'
+changequote([,])
+  dnl eval is necessary to expand gl_absname_cpp.
+  dnl Ultrix and Pyramid sh refuse to redirect output of eval,
+  dnl so use subshell.
+  AS_VAR_SET([gl_cv_absolute_]AS_TR_SH([[$1]]),
+[`(eval "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
+  sed -n "$gl_absolute_header_sed"`])
+])
diff --git a/gl/m4/af_alg.m4 b/gl/m4/af_alg.m4
new file mode 100644
index 00000000..f4c0d624
--- /dev/null
+++ b/gl/m4/af_alg.m4
@@ -0,0 +1,57 @@
+# af_alg.m4 serial 6
+dnl Copyright 2018-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Matteo Croce.
+
+AC_DEFUN_ONCE([gl_AF_ALG],
+[
+  AC_REQUIRE([gl_SYS_SOCKET_H])
+  AC_REQUIRE([AC_C_INLINE])
+
+  dnl Check whether linux/if_alg.h has needed features.
+  AC_CACHE_CHECK([whether linux/if_alg.h has struct sockaddr_alg.],
+    [gl_cv_header_linux_if_alg_salg],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM([[#include <sys/socket.h>
+                          #include <linux/if_alg.h>
+                          struct sockaddr_alg salg = {
+                            .salg_family = AF_ALG,
+                            .salg_type = "hash",
+                            .salg_name = "sha1",
+                          };]])],
+       [gl_cv_header_linux_if_alg_salg=yes],
+       [gl_cv_header_linux_if_alg_salg=no])])
+  if test "$gl_cv_header_linux_if_alg_salg" = yes; then
+    AC_DEFINE([HAVE_LINUX_IF_ALG_H], [1],
+      [Define to 1 if you have 'struct sockaddr_alg' defined.])
+  fi
+
+  dnl The default is to not use AF_ALG if available,
+  dnl as it's system dependent as to whether the kernel
+  dnl routines are faster than libcrypto for example.
+  use_af_alg=no
+  AC_ARG_WITH([linux-crypto],
+    [AS_HELP_STRING([[--with-linux-crypto]],
+       [use Linux kernel cryptographic API (if available) for the hash functions
+        MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512 on files])],
+    [use_af_alg=$withval],
+    [use_af_alg=no])
+  dnl We cannot use it if it is not available.
+  if test "$gl_cv_header_linux_if_alg_salg" != yes; then
+    if test "$use_af_alg" != no; then
+      AC_MSG_WARN([Linux kernel cryptographic API not found])
+    fi
+    use_af_alg=no
+  fi
+
+  if test "$use_af_alg" != no; then
+    USE_AF_ALG=1
+  else
+    USE_AF_ALG=0
+  fi
+  AC_DEFINE_UNQUOTED([USE_LINUX_CRYPTO_API], [$USE_AF_ALG],
+    [Define to 1 if you want to use the Linux kernel cryptographic API.])
+])
diff --git a/gl/m4/alloca.m4 b/gl/m4/alloca.m4
index 270abd0c..c685fac9 100644
--- a/gl/m4/alloca.m4
+++ b/gl/m4/alloca.m4
@@ -1,5 +1,5 @@
-# alloca.m4 serial 14
-dnl Copyright (C) 2002-2004, 2006-2007, 2009-2013 Free Software Foundation,
+# alloca.m4 serial 21
+dnl Copyright (C) 2002-2004, 2006-2007, 2009-2023 Free Software Foundation,
 dnl Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -26,30 +26,35 @@ AC_DEFUN([gl_FUNC_ALLOCA],
       AC_DEFINE([HAVE_ALLOCA], [1],
         [Define to 1 if you have 'alloca' after including <alloca.h>,
          a header that may be supplied by this distribution.])
-      ALLOCA_H=alloca.h
+      GL_GENERATE_ALLOCA_H=true
     else
       dnl alloca exists as a library function, i.e. it is slow and probably
       dnl a memory leak. Don't define HAVE_ALLOCA in this case.
-      ALLOCA_H=
+      GL_GENERATE_ALLOCA_H=false
     fi
   else
-    ALLOCA_H=alloca.h
+    GL_GENERATE_ALLOCA_H=true
   fi
-  AC_SUBST([ALLOCA_H])
-  AM_CONDITIONAL([GL_GENERATE_ALLOCA_H], [test -n "$ALLOCA_H"])
+
+  if test $ac_cv_working_alloca_h = yes; then
+    HAVE_ALLOCA_H=1
+  else
+    HAVE_ALLOCA_H=0
+  fi
+  AC_SUBST([HAVE_ALLOCA_H])
 ])
 
 # Prerequisites of lib/alloca.c.
 # STACK_DIRECTION is already handled by AC_FUNC_ALLOCA.
 AC_DEFUN([gl_PREREQ_ALLOCA], [:])
 
-# This works around a bug in autoconf <= 2.68.
-# See <http://lists.gnu.org/archive/html/bug-gnulib/2011-06/msg00277.html>.
+m4_version_prereq([2.70], [], [
 
-m4_version_prereq([2.69], [] ,[
-
-# This is taken from the following Autoconf patch:
-# http://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=6cd9f12520b0d6f76d3230d7565feba1ecf29497
+# This works around a bug in autoconf <= 2.68 and has simplifications
+# from 2.70.  See:
+# https://lists.gnu.org/r/bug-gnulib/2011-06/msg00277.html
+# https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=6cd9f12520b0d6f76d3230d7565feba1ecf29497
+# https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=15edf7fd8094fd14a89d9891dd72a9624762597a
 
 # _AC_LIBOBJ_ALLOCA
 # -----------------
@@ -65,26 +70,6 @@ AC_LIBSOURCES(alloca.c)
 AC_SUBST([ALLOCA], [\${LIBOBJDIR}alloca.$ac_objext])dnl
 AC_DEFINE(C_ALLOCA, 1, [Define to 1 if using 'alloca.c'.])
 
-AC_CACHE_CHECK(whether 'alloca.c' needs Cray hooks, ac_cv_os_cray,
-[AC_EGREP_CPP(webecray,
-[#if defined CRAY && ! defined CRAY2
-webecray
-#else
-wenotbecray
-#endif
-], ac_cv_os_cray=yes, ac_cv_os_cray=no)])
-if test $ac_cv_os_cray = yes; then
-  for ac_func in _getb67 GETB67 getb67; do
-    AC_CHECK_FUNC($ac_func,
-                  [AC_DEFINE_UNQUOTED(CRAY_STACKSEG_END, $ac_func,
-                                      [Define to one of '_getb67', 'GETB67',
-                                       'getb67' for Cray-2 and Cray-YMP
-                                       systems. This function is required for
-                                       'alloca.c' support on those systems.])
-    break])
-  done
-fi
-
 AC_CACHE_CHECK([stack direction for C alloca],
                [ac_cv_c_stack_direction],
 [AC_RUN_IFELSE([AC_LANG_SOURCE(
@@ -115,7 +100,7 @@ AH_VERBATIM([STACK_DIRECTION],
         STACK_DIRECTION > 0 => grows toward higher addresses
         STACK_DIRECTION < 0 => grows toward lower addresses
         STACK_DIRECTION = 0 => direction of growth unknown */
-@%:@undef STACK_DIRECTION])dnl
+#undef STACK_DIRECTION])dnl
 AC_DEFINE_UNQUOTED(STACK_DIRECTION, $ac_cv_c_stack_direction)
 ])# _AC_LIBOBJ_ALLOCA
 ])
diff --git a/gl/m4/arpa_inet_h.m4 b/gl/m4/arpa_inet_h.m4
index ea69af57..fa5fe831 100644
--- a/gl/m4/arpa_inet_h.m4
+++ b/gl/m4/arpa_inet_h.m4
@@ -1,15 +1,15 @@
-# arpa_inet_h.m4 serial 13
-dnl Copyright (C) 2006, 2008-2013 Free Software Foundation, Inc.
+# arpa_inet_h.m4 serial 17
+dnl Copyright (C) 2006, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl Written by Simon Josefsson and Bruno Haible
 
-AC_DEFUN([gl_HEADER_ARPA_INET],
+AC_DEFUN_ONCE([gl_ARPA_INET_H],
 [
-  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
-  dnl once only, before all statements that occur in other macros.
+  dnl Ensure to expand the default settings once only, before all statements
+  dnl that occur in other macros.
   AC_REQUIRE([gl_ARPA_INET_H_DEFAULTS])
 
   AC_CHECK_HEADERS_ONCE([arpa/inet.h])
@@ -24,6 +24,8 @@ AC_DEFUN([gl_HEADER_ARPA_INET],
 
   AC_REQUIRE([gl_FEATURES_H])
 
+  gl_PREREQ_SYS_H_WS2TCPIP
+
   dnl Check for declarations of anything we want to poison if the
   dnl corresponding gnulib module is not in use.
   gl_WARN_ON_USE_PREPARE([[
@@ -38,17 +40,32 @@ AC_DEFUN([gl_HEADER_ARPA_INET],
     ]], [inet_ntop inet_pton])
 ])
 
+# gl_ARPA_INET_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_ARPA_INET_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_ARPA_INET_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_ARPA_INET_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_ARPA_INET_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_ARPA_INET_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_INET_NTOP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_INET_PTON])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_ARPA_INET_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_ARPA_INET_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_ARPA_INET_H_DEFAULTS],
 [
-  GNULIB_INET_NTOP=0;     AC_SUBST([GNULIB_INET_NTOP])
-  GNULIB_INET_PTON=0;     AC_SUBST([GNULIB_INET_PTON])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_DECL_INET_NTOP=1;  AC_SUBST([HAVE_DECL_INET_NTOP])
   HAVE_DECL_INET_PTON=1;  AC_SUBST([HAVE_DECL_INET_PTON])
diff --git a/gl/m4/assert_h.m4 b/gl/m4/assert_h.m4
new file mode 100644
index 00000000..abba4fa3
--- /dev/null
+++ b/gl/m4/assert_h.m4
@@ -0,0 +1,67 @@
+# assert-h.m4
+dnl Copyright (C) 2011-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Paul Eggert.
+
+AC_DEFUN([gl_ASSERT_H],
+[
+  AC_CACHE_CHECK([for static_assert], [gl_cv_static_assert],
+    [gl_save_CFLAGS=$CFLAGS
+     for gl_working in "yes, a keyword" "yes, an <assert.h> macro"; do
+      AS_CASE([$gl_working],
+        [*assert.h*], [CFLAGS="$gl_save_CFLAGS -DINCLUDE_ASSERT_H"])
+
+      AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#if defined __clang__ && __STDC_VERSION__ < 202311
+             #pragma clang diagnostic error "-Wc2x-extensions"
+             #pragma clang diagnostic error "-Wc++17-extensions"
+            #endif
+            #ifdef INCLUDE_ASSERT_H
+             #include <assert.h>
+            #endif
+            static_assert (2 + 2 == 4, "arithmetic does not work");
+            static_assert (2 + 2 == 4);
+          ]],
+          [[
+            static_assert (sizeof (char) == 1, "sizeof does not work");
+            static_assert (sizeof (char) == 1);
+          ]])],
+       [gl_cv_static_assert=$gl_working],
+       [gl_cv_static_assert=no])
+      CFLAGS=$gl_save_CFLAGS
+      test "$gl_cv_static_assert" != no && break
+     done])
+
+  GL_GENERATE_ASSERT_H=false
+  AS_CASE([$gl_cv_static_assert],
+    [yes*keyword*],
+      [AC_DEFINE([HAVE_C_STATIC_ASSERT], [1],
+         [Define to 1 if the static_assert keyword works.])],
+    [no],
+      [GL_GENERATE_ASSERT_H=true
+       gl_NEXT_HEADERS([assert.h])])
+
+  dnl The "zz" puts this toward config.h's end, to avoid potential
+  dnl collisions with other definitions.  #undef assert so that
+  dnl programs are not tempted to use it without specifically
+  dnl including assert.h.  Break the #undef apart with a comment
+  dnl so that 'configure' does not comment it out.
+  AH_VERBATIM([zzstatic_assert],
+[#if (!defined HAVE_C_STATIC_ASSERT && !defined assert \
+     && (!defined __cplusplus \
+         || (__cpp_static_assert < 201411 \
+             && __GNUG__ < 6 && __clang_major__ < 6)))
+ #include <assert.h>
+ #undef/**/assert
+ /* Solaris 11.4 <assert.h> defines static_assert as a macro with 2 arguments.
+    We need it also to be invocable with a single argument.  */
+ #if defined __sun && (__STDC_VERSION__ - 0 >= 201112L) && !defined __cplusplus
+  #undef/**/static_assert
+  #define static_assert _Static_assert
+ #endif
+#endif])
+])
diff --git a/gl/m4/base64.m4 b/gl/m4/base64.m4
index fc19893e..987930ab 100644
--- a/gl/m4/base64.m4
+++ b/gl/m4/base64.m4
@@ -1,5 +1,5 @@
 # base64.m4 serial 4
-dnl Copyright (C) 2004, 2006, 2009-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2004, 2006, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/btowc.m4 b/gl/m4/btowc.m4
index 978a06e9..77218a7d 100644
--- a/gl/m4/btowc.m4
+++ b/gl/m4/btowc.m4
@@ -1,5 +1,5 @@
-# btowc.m4 serial 10
-dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
+# btowc.m4 serial 12
+dnl Copyright (C) 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -10,7 +10,7 @@ AC_DEFUN([gl_FUNC_BTOWC],
 
   dnl Check whether <wchar.h> is usable at all, first. Otherwise the test
   dnl program below may lead to an endless loop. See
-  dnl <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42440>.
+  dnl <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42440>.
   AC_REQUIRE([gl_WCHAR_H_INLINE_OK])
 
   AC_CHECK_FUNCS_ONCE([btowc])
@@ -28,14 +28,6 @@ AC_DEFUN([gl_FUNC_BTOWC],
       [
         AC_RUN_IFELSE(
           [AC_LANG_SOURCE([[
-#include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -50,6 +42,8 @@ changequote(,)dnl
            case "$host_os" in
                       # Guess no on Cygwin.
              cygwin*) gl_cv_func_btowc_nul="guessing no" ;;
+                      # Guess yes on native Windows.
+             mingw*)  gl_cv_func_btowc_nul="guessing yes" ;;
                       # Guess yes otherwise.
              *)       gl_cv_func_btowc_nul="guessing yes" ;;
            esac
@@ -65,24 +59,19 @@ changequote([,])dnl
         dnl is present.
 changequote(,)dnl
         case "$host_os" in
-                 # Guess no on IRIX.
-          irix*) gl_cv_func_btowc_eof="guessing no" ;;
-                 # Guess yes otherwise.
-          *)     gl_cv_func_btowc_eof="guessing yes" ;;
+                  # Guess no on IRIX.
+          irix*)  gl_cv_func_btowc_eof="guessing no" ;;
+                  # Guess yes on native Windows.
+          mingw*) gl_cv_func_btowc_eof="guessing yes" ;;
+                  # Guess yes otherwise.
+          *)      gl_cv_func_btowc_eof="guessing yes" ;;
         esac
 changequote([,])dnl
         if test $LOCALE_FR != none; then
           AC_RUN_IFELSE(
             [AC_LANG_SOURCE([[
 #include <locale.h>
-#include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
 #include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
diff --git a/gl/m4/builtin-expect.m4 b/gl/m4/builtin-expect.m4
new file mode 100644
index 00000000..531ed48a
--- /dev/null
+++ b/gl/m4/builtin-expect.m4
@@ -0,0 +1,49 @@
+dnl Check for __builtin_expect.
+
+dnl Copyright 2016-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Paul Eggert.
+
+AC_DEFUN([gl___BUILTIN_EXPECT],
+[
+  AC_CACHE_CHECK([for __builtin_expect],
+    [gl_cv___builtin_expect],
+    [AC_LINK_IFELSE(
+       [AC_LANG_SOURCE([[
+         int
+         main (int argc, char **argv)
+         {
+           argc = __builtin_expect (argc, 100);
+           return argv[argc != 100][0];
+         }]])],
+       [gl_cv___builtin_expect=yes],
+       [AC_LINK_IFELSE(
+          [AC_LANG_SOURCE([[
+             #include <builtins.h>
+             int
+             main (int argc, char **argv)
+             {
+               argc = __builtin_expect (argc, 100);
+               return argv[argc != 100][0];
+             }]])],
+          [gl_cv___builtin_expect="in <builtins.h>"],
+          [gl_cv___builtin_expect=no])])])
+  if test "$gl_cv___builtin_expect" = yes; then
+    AC_DEFINE([HAVE___BUILTIN_EXPECT], [1])
+  elif test "$gl_cv___builtin_expect" = "in <builtins.h>"; then
+    AC_DEFINE([HAVE___BUILTIN_EXPECT], [2])
+  fi
+  AH_VERBATIM([HAVE___BUILTIN_EXPECT],
+    [/* Define to 1 if the compiler supports __builtin_expect,
+   and to 2 if <builtins.h> does.  */
+#undef HAVE___BUILTIN_EXPECT
+#ifndef HAVE___BUILTIN_EXPECT
+# define __builtin_expect(e, c) (e)
+#elif HAVE___BUILTIN_EXPECT == 2
+# include <builtins.h>
+#endif
+    ])
+])
diff --git a/gl/m4/byteswap.m4 b/gl/m4/byteswap.m4
new file mode 100644
index 00000000..8058d178
--- /dev/null
+++ b/gl/m4/byteswap.m4
@@ -0,0 +1,17 @@
+# byteswap.m4 serial 5
+dnl Copyright (C) 2005, 2007, 2009-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Oskar Liljeblad.
+
+AC_DEFUN([gl_BYTESWAP],
+[
+  dnl Prerequisites of lib/byteswap.in.h.
+  AC_CHECK_HEADERS([byteswap.h], [
+    GL_GENERATE_BYTESWAP_H=false
+  ], [
+    GL_GENERATE_BYTESWAP_H=true
+  ])
+])
diff --git a/gl/m4/c-bool.m4 b/gl/m4/c-bool.m4
new file mode 100644
index 00000000..f614371b
--- /dev/null
+++ b/gl/m4/c-bool.m4
@@ -0,0 +1,51 @@
+# Check for bool that conforms to C2023.
+
+dnl Copyright 2022-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_C_BOOL],
+[
+  AC_CACHE_CHECK([for bool, true, false], [gl_cv_c_bool],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_SOURCE([[
+          #if true == false
+           #error "true == false"
+          #endif
+          extern bool b;
+          bool b = true == false;]])],
+       [gl_cv_c_bool=yes],
+       [gl_cv_c_bool=no])])
+  if test "$gl_cv_c_bool" = yes; then
+    AC_DEFINE([HAVE_C_BOOL], [1],
+      [Define to 1 if bool, true and false work as per C2023.])
+  fi
+
+  AC_CHECK_HEADERS_ONCE([stdbool.h])
+
+  dnl The "zz" puts this toward config.h's end, to avoid potential
+  dnl collisions with other definitions.
+  dnl If 'bool', 'true' and 'false' do not work, arrange for them to work.
+  dnl In C, this means including <stdbool.h> if it is not already included.
+  dnl However, if the preprocessor mistakenly treats 'true' as 0,
+  dnl define it to a bool expression equal to 1; this is needed in
+  dnl Sun C++ 5.11 (Oracle Solaris Studio 12.2, 2010) and older.
+  AH_VERBATIM([zzbool],
+[#ifndef HAVE_C_BOOL
+# if !defined __cplusplus && !defined __bool_true_false_are_defined
+#  if HAVE_STDBOOL_H
+#   include <stdbool.h>
+#  else
+#   if defined __SUNPRO_C
+#    error "<stdbool.h> is not usable with this configuration. To make it usable, add -D_STDC_C99= to $CC."
+#   else
+#    error "<stdbool.h> does not exist on this platform. Use gnulib module 'stdbool-c99' instead of gnulib module 'stdbool'."
+#   endif
+#  endif
+# endif
+# if !true
+#  define true (!false)
+# endif
+#endif])
+])
diff --git a/gl/m4/calloc.m4 b/gl/m4/calloc.m4
new file mode 100644
index 00000000..23c0dd9f
--- /dev/null
+++ b/gl/m4/calloc.m4
@@ -0,0 +1,83 @@
+# calloc.m4 serial 29
+
+# Copyright (C) 2004-2023 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Written by Jim Meyering.
+
+# Determine whether calloc (N, S) returns non-NULL when N*S is zero,
+# and returns NULL when N*S overflows.
+# If so, define HAVE_CALLOC.  Otherwise, define calloc to rpl_calloc
+# and arrange to use a calloc wrapper function that does work in that case.
+
+# _AC_FUNC_CALLOC_IF([IF-WORKS], [IF-NOT])
+# -------------------------------------
+# If calloc is compatible with GNU calloc, run IF-WORKS, otherwise, IF-NOT.
+AC_DEFUN([_AC_FUNC_CALLOC_IF],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether calloc (0, n) and calloc (n, 0) return nonnull],
+    [ac_cv_func_calloc_0_nonnull],
+    [if test $cross_compiling != yes; then
+       ac_cv_func_calloc_0_nonnull=yes
+       AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+            [AC_INCLUDES_DEFAULT],
+            [[int result = 0;
+              char * volatile p = calloc (0, 0);
+              if (!p)
+                result |= 1;
+              free (p);
+              return result;
+            ]])],
+         [],
+         [ac_cv_func_calloc_0_nonnull=no])
+     else
+       case "$host_os" in
+                        # Guess yes on glibc systems.
+         *-gnu* | gnu*) ac_cv_func_calloc_0_nonnull="guessing yes" ;;
+                        # Guess yes on musl systems.
+         *-musl*)       ac_cv_func_calloc_0_nonnull="guessing yes" ;;
+                        # Guess yes on native Windows.
+         mingw*)        ac_cv_func_calloc_0_nonnull="guessing yes" ;;
+                        # If we don't know, obey --enable-cross-guesses.
+         *)             ac_cv_func_calloc_0_nonnull="$gl_cross_guess_normal" ;;
+       esac
+     fi
+    ])
+  AS_CASE([$ac_cv_func_calloc_0_nonnull], [*yes], [$1], [$2])
+])
+
+
+# gl_FUNC_CALLOC_GNU
+# ------------------
+# Replace calloc if it is not compatible with GNU libc.
+AC_DEFUN([gl_FUNC_CALLOC_GNU],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_CALLOC_POSIX])
+  REPLACE_CALLOC_FOR_CALLOC_GNU="$REPLACE_CALLOC_FOR_CALLOC_POSIX"
+  if test $REPLACE_CALLOC_FOR_CALLOC_GNU = 0; then
+    _AC_FUNC_CALLOC_IF([], [REPLACE_CALLOC_FOR_CALLOC_GNU=1])
+  fi
+])# gl_FUNC_CALLOC_GNU
+
+# gl_FUNC_CALLOC_POSIX
+# --------------------
+# Test whether 'calloc' is POSIX compliant (sets errno to ENOMEM when it
+# fails, and doesn't mess up with ptrdiff_t or size_t overflow),
+# and replace calloc if it is not.
+AC_DEFUN([gl_FUNC_CALLOC_POSIX],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_MALLOC_POSIX])
+  if test $REPLACE_MALLOC_FOR_MALLOC_POSIX = 1; then
+    REPLACE_CALLOC_FOR_CALLOC_POSIX=1
+  fi
+  dnl Although in theory we should also test for size_t overflow,
+  dnl in practice testing for ptrdiff_t overflow suffices
+  dnl since PTRDIFF_MAX <= SIZE_MAX on all known Gnulib porting targets.
+  dnl A separate size_t test would slow down 'configure'.
+])
diff --git a/gl/m4/close.m4 b/gl/m4/close.m4
new file mode 100644
index 00000000..9f95c670
--- /dev/null
+++ b/gl/m4/close.m4
@@ -0,0 +1,35 @@
+# close.m4 serial 9
+dnl Copyright (C) 2008-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_CLOSE],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  m4_ifdef([gl_MSVC_INVAL], [
+    AC_REQUIRE([gl_MSVC_INVAL])
+    if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
+      REPLACE_CLOSE=1
+    fi
+  ])
+  m4_ifdef([gl_PREREQ_SYS_H_WINSOCK2], [
+    gl_PREREQ_SYS_H_WINSOCK2
+    if test $UNISTD_H_HAVE_WINSOCK2_H = 1; then
+      dnl Even if the 'socket' module is not used here, another part of the
+      dnl application may use it and pass file descriptors that refer to
+      dnl sockets to the close() function. So enable the support for sockets.
+      REPLACE_CLOSE=1
+    fi
+  ])
+  dnl Replace close() for supporting the gnulib-defined fchdir() function,
+  dnl to keep fchdir's bookkeeping up-to-date.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    if test $REPLACE_CLOSE = 0; then
+      gl_TEST_FCHDIR
+      if test $HAVE_FCHDIR = 0; then
+        REPLACE_CLOSE=1
+      fi
+    fi
+  ])
+])
diff --git a/gl/m4/codeset.m4 b/gl/m4/codeset.m4
index c2761be2..5804f472 100644
--- a/gl/m4/codeset.m4
+++ b/gl/m4/codeset.m4
@@ -1,5 +1,6 @@
 # codeset.m4 serial 5 (gettext-0.18.2)
-dnl Copyright (C) 2000-2002, 2006, 2008-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2000-2002, 2006, 2008-2014, 2016, 2019-2023 Free Software
+dnl Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/configmake.m4 b/gl/m4/configmake.m4
deleted file mode 100644
index 823ffc0d..00000000
--- a/gl/m4/configmake.m4
+++ /dev/null
@@ -1,50 +0,0 @@
-# configmake.m4 serial 1
-dnl Copyright (C) 2010-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-# gl_CONFIGMAKE_PREP
-# ------------------
-# Guarantee all of the standard directory variables, even when used with
-# autoconf 2.59 (datarootdir wasn't supported until 2.59c) or automake
-# 1.9.6 (pkglibexecdir wasn't supported until 1.10b.).
-AC_DEFUN([gl_CONFIGMAKE_PREP],
-[
-  dnl Technically, datadir should default to datarootdir.  But if
-  dnl autoconf is too old to provide datarootdir, then reversing the
-  dnl definition is a reasonable compromise.  Only AC_SUBST a variable
-  dnl if it was not already defined earlier by autoconf.
-  if test "x$datarootdir" = x; then
-    AC_SUBST([datarootdir], ['${datadir}'])
-  fi
-  dnl Copy the approach used in autoconf 2.60.
-  if test "x$docdir" = x; then
-    AC_SUBST([docdir], [m4_ifset([AC_PACKAGE_TARNAME],
-      ['${datarootdir}/doc/${PACKAGE_TARNAME}'],
-      ['${datarootdir}/doc/${PACKAGE}'])])
-  fi
-  dnl The remaining variables missing from autoconf 2.59 are easier.
-  if test "x$htmldir" = x; then
-    AC_SUBST([htmldir], ['${docdir}'])
-  fi
-  if test "x$dvidir" = x; then
-    AC_SUBST([dvidir], ['${docdir}'])
-  fi
-  if test "x$pdfdir" = x; then
-    AC_SUBST([pdfdir], ['${docdir}'])
-  fi
-  if test "x$psdir" = x; then
-    AC_SUBST([psdir], ['${docdir}'])
-  fi
-  if test "x$lispdir" = x; then
-    AC_SUBST([lispdir], ['${datarootdir}/emacs/site-lisp'])
-  fi
-  if test "x$localedir" = x; then
-    AC_SUBST([localedir], ['${datarootdir}/locale'])
-  fi
-
-  dnl Automake 1.9.6 only lacks pkglibexecdir; and since 1.11 merely
-  dnl provides it without AC_SUBST, this blind use of AC_SUBST is safe.
-  AC_SUBST([pkglibexecdir], ['${libexecdir}/${PACKAGE}'])
-])
diff --git a/gl/m4/dirname.m4 b/gl/m4/dirname.m4
deleted file mode 100644
index 5897a2a8..00000000
--- a/gl/m4/dirname.m4
+++ /dev/null
@@ -1,19 +0,0 @@
-#serial 10   -*- autoconf -*-
-dnl Copyright (C) 2002-2006, 2009-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-AC_DEFUN([gl_DIRNAME],
-[
-  AC_REQUIRE([gl_DIRNAME_LGPL])
-])
-
-AC_DEFUN([gl_DIRNAME_LGPL],
-[
-  dnl Prerequisites of lib/dirname.h.
-  AC_REQUIRE([gl_DOUBLE_SLASH_ROOT])
-
-  dnl No prerequisites of lib/basename-lgpl.c, lib/dirname-lgpl.c,
-  dnl lib/stripslash.c.
-])
diff --git a/gl/m4/double-slash-root.m4 b/gl/m4/double-slash-root.m4
index bd6f8671..1776e5eb 100644
--- a/gl/m4/double-slash-root.m4
+++ b/gl/m4/double-slash-root.m4
@@ -1,5 +1,5 @@
 # double-slash-root.m4 serial 4   -*- Autoconf -*-
-dnl Copyright (C) 2006, 2008-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2006, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/dup2.m4 b/gl/m4/dup2.m4
new file mode 100644
index 00000000..e1cc73e1
--- /dev/null
+++ b/gl/m4/dup2.m4
@@ -0,0 +1,105 @@
+#serial 27
+dnl Copyright (C) 2002, 2005, 2007, 2009-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_DUP2],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
+    [AC_RUN_IFELSE([
+       AC_LANG_PROGRAM(
+         [[#include <errno.h>
+           #include <fcntl.h>
+           #include <limits.h>
+           #include <sys/resource.h>
+           #include <unistd.h>
+           ]GL_MDA_DEFINES[
+           #ifndef RLIM_SAVED_CUR
+           # define RLIM_SAVED_CUR RLIM_INFINITY
+           #endif
+           #ifndef RLIM_SAVED_MAX
+           # define RLIM_SAVED_MAX RLIM_INFINITY
+           #endif
+         ]],
+         [[int result = 0;
+           int bad_fd = INT_MAX;
+           struct rlimit rlim;
+           if (getrlimit (RLIMIT_NOFILE, &rlim) == 0
+               && 0 <= rlim.rlim_cur && rlim.rlim_cur <= INT_MAX
+               && rlim.rlim_cur != RLIM_INFINITY
+               && rlim.rlim_cur != RLIM_SAVED_MAX
+               && rlim.rlim_cur != RLIM_SAVED_CUR)
+             bad_fd = rlim.rlim_cur;
+           #ifdef FD_CLOEXEC
+             if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
+               result |= 1;
+           #endif
+           if (dup2 (1, 1) != 1)
+             result |= 2;
+           #ifdef FD_CLOEXEC
+             if (fcntl (1, F_GETFD) != FD_CLOEXEC)
+               result |= 4;
+           #endif
+           close (0);
+           if (dup2 (0, 0) != -1)
+             result |= 8;
+           /* Many gnulib modules require POSIX conformance of EBADF.  */
+           if (dup2 (2, bad_fd) == -1 && errno != EBADF)
+             result |= 16;
+           /* Flush out some cygwin core dumps.  */
+           if (dup2 (2, -1) != -1 || errno != EBADF)
+             result |= 32;
+           dup2 (2, 255);
+           dup2 (2, 256);
+           /* On OS/2 kLIBC, dup2() does not work on a directory fd.  */
+           {
+             int fd = open (".", O_RDONLY);
+             if (fd == -1)
+               result |= 64;
+             else if (dup2 (fd, fd + 1) == -1)
+               result |= 128;
+             close (fd);
+           }
+           return result;]])
+      ],
+      [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
+      [case "$host_os" in
+         mingw*) # on this platform, dup2 always returns 0 for success
+           gl_cv_func_dup2_works="guessing no" ;;
+         cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
+           gl_cv_func_dup2_works="guessing no" ;;
+         aix* | freebsd*)
+                 # on AIX 7.1 and FreeBSD 6.1, dup2 (1,toobig) gives EMFILE,
+                 # not EBADF.
+           gl_cv_func_dup2_works="guessing no" ;;
+         haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC.
+           gl_cv_func_dup2_works="guessing no" ;;
+         *-android*) # implemented using dup3(), which fails if oldfd == newfd
+           gl_cv_func_dup2_works="guessing no" ;;
+         os2*) # on OS/2 kLIBC, dup2() does not work on a directory fd.
+           gl_cv_func_dup2_works="guessing no" ;;
+         *) gl_cv_func_dup2_works="guessing yes" ;;
+       esac])
+    ])
+  case "$gl_cv_func_dup2_works" in
+    *yes) ;;
+    *)
+      REPLACE_DUP2=1
+      AC_CHECK_FUNCS([setdtablesize])
+      ;;
+  esac
+  dnl Replace dup2() for supporting the gnulib-defined fchdir() function,
+  dnl to keep fchdir's bookkeeping up-to-date.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    gl_TEST_FCHDIR
+    if test $HAVE_FCHDIR = 0; then
+      REPLACE_DUP2=1
+    fi
+  ])
+])
+
+# Prerequisites of lib/dup2.c.
+AC_DEFUN([gl_PREREQ_DUP2], [])
diff --git a/gl/m4/eealloc.m4 b/gl/m4/eealloc.m4
index c640ec12..cb3e08fe 100644
--- a/gl/m4/eealloc.m4
+++ b/gl/m4/eealloc.m4
@@ -1,5 +1,5 @@
 # eealloc.m4 serial 3
-dnl Copyright (C) 2003, 2009-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2003, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/environ.m4 b/gl/m4/environ.m4
index 593a33ed..741dfc56 100644
--- a/gl/m4/environ.m4
+++ b/gl/m4/environ.m4
@@ -1,5 +1,5 @@
-# environ.m4 serial 6
-dnl Copyright (C) 2001-2004, 2006-2013 Free Software Foundation, Inc.
+# environ.m4 serial 8
+dnl Copyright (C) 2001-2004, 2006-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -29,16 +29,15 @@ AC_DEFUN_ONCE([gl_ENVIRON],
 AC_DEFUN([gt_CHECK_VAR_DECL],
 [
   define([gt_cv_var], [gt_cv_var_]$2[_declaration])
-  AC_MSG_CHECKING([if $2 is properly declared])
-  AC_CACHE_VAL([gt_cv_var], [
-    AC_COMPILE_IFELSE(
-      [AC_LANG_PROGRAM(
-         [[$1
-           extern struct { int foo; } $2;]],
-         [[$2.foo = 1;]])],
-      [gt_cv_var=no],
-      [gt_cv_var=yes])])
-  AC_MSG_RESULT([$gt_cv_var])
+  AC_CACHE_CHECK([if $2 is properly declared], [gt_cv_var],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[$1
+            typedef struct { int foo; } foo_t;
+            extern foo_t $2;]],
+          [[$2.foo = 1;]])],
+       [gt_cv_var=no],
+       [gt_cv_var=yes])])
   if test $gt_cv_var = yes; then
     AC_DEFINE([HAVE_]m4_translit($2, [a-z], [A-Z])[_DECL], 1,
               [Define if you have the declaration of $2.])
diff --git a/gl/m4/errno_h.m4 b/gl/m4/errno_h.m4
index c813ea58..4c70d225 100644
--- a/gl/m4/errno_h.m4
+++ b/gl/m4/errno_h.m4
@@ -1,9 +1,11 @@
-# errno_h.m4 serial 12
-dnl Copyright (C) 2004, 2006, 2008-2013 Free Software Foundation, Inc.
+# errno_h.m4 serial 14
+dnl Copyright (C) 2004, 2006, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
+AC_PREREQ([2.61])
+
 AC_DEFUN_ONCE([gl_HEADER_ERRNO_H],
 [
   AC_REQUIRE([AC_PROG_CC])
@@ -66,13 +68,11 @@ booboo
       [gl_cv_header_errno_h_complete=yes])
   ])
   if test $gl_cv_header_errno_h_complete = yes; then
-    ERRNO_H=''
+    GL_GENERATE_ERRNO_H=false
   else
     gl_NEXT_HEADERS([errno.h])
-    ERRNO_H='errno.h'
+    GL_GENERATE_ERRNO_H=true
   fi
-  AC_SUBST([ERRNO_H])
-  AM_CONDITIONAL([GL_GENERATE_ERRNO_H], [test -n "$ERRNO_H"])
   gl_REPLACE_ERRNO_VALUE([EMULTIHOP])
   gl_REPLACE_ERRNO_VALUE([ENOLINK])
   gl_REPLACE_ERRNO_VALUE([EOVERFLOW])
@@ -86,7 +86,7 @@ booboo
 # Set the variables EOVERFLOW_HIDDEN and EOVERFLOW_VALUE.
 AC_DEFUN([gl_REPLACE_ERRNO_VALUE],
 [
-  if test -n "$ERRNO_H"; then
+  if $GL_GENERATE_ERRNO_H; then
     AC_CACHE_CHECK([for ]$1[ value], [gl_cv_header_errno_h_]$1, [
       AC_EGREP_CPP([yes],[
 #include <errno.h>
@@ -129,9 +129,3 @@ yes
     AC_SUBST($1[_VALUE])
   fi
 ])
-
-dnl Autoconf >= 2.61 has AC_COMPUTE_INT built-in.
-dnl Remove this when we can assume autoconf >= 2.61.
-m4_ifdef([AC_COMPUTE_INT], [], [
-  AC_DEFUN([AC_COMPUTE_INT], [_AC_COMPUTE_INT([$2],[$1],[$3],[$4])])
-])
diff --git a/gl/m4/error.m4 b/gl/m4/error.m4
index 29e6fdc9..8cc75dff 100644
--- a/gl/m4/error.m4
+++ b/gl/m4/error.m4
@@ -1,6 +1,6 @@
-#serial 14
+#serial 15
 
-# Copyright (C) 1996-1998, 2001-2004, 2009-2013 Free Software Foundation, Inc.
+# Copyright (C) 1996-1998, 2001-2004, 2009-2023 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -22,6 +22,10 @@ AC_DEFUN([gl_ERROR],
 # Prerequisites of lib/error.c.
 AC_DEFUN([gl_PREREQ_ERROR],
 [
+  dnl Use system extensions on Android, so that AC_FUNC_STRERROR_R
+  dnl discovers the GNU API for strerror_r on Android API level 23 and later.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   AC_REQUIRE([AC_FUNC_STRERROR_R])
   :
 ])
diff --git a/gl/m4/exponentd.m4 b/gl/m4/exponentd.m4
index 09df468c..2ef46437 100644
--- a/gl/m4/exponentd.m4
+++ b/gl/m4/exponentd.m4
@@ -1,5 +1,5 @@
 # exponentd.m4 serial 3
-dnl Copyright (C) 2007-2008, 2010-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2007-2008, 2010-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/extensions.m4 b/gl/m4/extensions.m4
index e30f1220..5336b8da 100644
--- a/gl/m4/extensions.m4
+++ b/gl/m4/extensions.m4
@@ -1,14 +1,19 @@
-# serial 13  -*- Autoconf -*-
+# serial 23  -*- Autoconf -*-
 # Enable extensions on systems that normally disable them.
 
-# Copyright (C) 2003, 2006-2013 Free Software Foundation, Inc.
+# Copyright (C) 2003, 2006-2023 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
+dnl Define to empty for the benefit of Autoconf 2.69 and earlier, so that
+dnl AC_USE_SYSTEM_EXTENSIONS (below) can be used unchanged from Autoconf 2.70+.
+m4_ifndef([AC_CHECK_INCLUDES_DEFAULT],
+  [AC_DEFUN([AC_CHECK_INCLUDES_DEFAULT], [])])
+
 # This definition of AC_USE_SYSTEM_EXTENSIONS is stolen from git
 # Autoconf.  Perhaps we can remove this once we can assume Autoconf
-# 2.70 or later everywhere, but since Autoconf mutates rapidly
+# is recent-enough everywhere, but since Autoconf mutates rapidly
 # enough in this area it's likely we'll need to redefine
 # AC_USE_SYSTEM_EXTENSIONS for quite some time.
 
@@ -26,67 +31,125 @@
 #      its dependencies. This will ensure that the gl_USE_SYSTEM_EXTENSIONS
 #      invocation occurs in gl_EARLY, not in gl_INIT.
 
+m4_version_prereq([2.72], [], [
+
 # AC_USE_SYSTEM_EXTENSIONS
 # ------------------------
 # Enable extensions on systems that normally disable them,
 # typically due to standards-conformance issues.
-#
-# Remember that #undef in AH_VERBATIM gets replaced with #define by
-# AC_DEFINE.  The goal here is to define all known feature-enabling
-# macros, then, if reports of conflicts are made, disable macros that
-# cause problems on some platforms (such as __EXTENSIONS__).
+# We unconditionally define as many of the known feature-enabling
+# as possible, reserving conditional behavior for macros that are
+# known to cause problems on some platforms (such as __EXTENSIONS__).
 AC_DEFUN_ONCE([AC_USE_SYSTEM_EXTENSIONS],
-[AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl
+[AC_BEFORE([$0], [AC_PREPROC_IFELSE])dnl
+AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl
+AC_BEFORE([$0], [AC_LINK_IFELSE])dnl
 AC_BEFORE([$0], [AC_RUN_IFELSE])dnl
-
-  AC_CHECK_HEADER([minix/config.h], [MINIX=yes], [MINIX=])
-  if test "$MINIX" = yes; then
-    AC_DEFINE([_POSIX_SOURCE], [1],
-      [Define to 1 if you need to in order for 'stat' and other
-       things to work.])
-    AC_DEFINE([_POSIX_1_SOURCE], [2],
-      [Define to 2 if the system does not provide POSIX.1 features
-       except with this defined.])
-    AC_DEFINE([_MINIX], [1],
-      [Define to 1 if on MINIX.])
-    AC_DEFINE([_NETBSD_SOURCE], [1],
-      [Define to 1 to make NetBSD features available.  MINIX 3 needs this.])
-  fi
-
+AC_BEFORE([$0], [AC_CHECK_INCLUDES_DEFAULT])dnl
+dnl #undef in AH_VERBATIM gets replaced with #define by AC_DEFINE.
 dnl Use a different key than __EXTENSIONS__, as that name broke existing
 dnl configure.ac when using autoheader 2.62.
-  AH_VERBATIM([USE_SYSTEM_EXTENSIONS],
+dnl The macros below are in alphabetical order ignoring leading _ or __
+dnl prefixes.
+AH_VERBATIM([USE_SYSTEM_EXTENSIONS],
 [/* Enable extensions on AIX 3, Interix.  */
 #ifndef _ALL_SOURCE
 # undef _ALL_SOURCE
 #endif
-/* Enable general extensions on OS X.  */
+/* Enable general extensions on macOS.  */
 #ifndef _DARWIN_C_SOURCE
 # undef _DARWIN_C_SOURCE
 #endif
+/* Enable general extensions on Solaris.  */
+#ifndef __EXTENSIONS__
+# undef __EXTENSIONS__
+#endif
 /* Enable GNU extensions on systems that have them.  */
 #ifndef _GNU_SOURCE
 # undef _GNU_SOURCE
 #endif
-/* Enable threading extensions on Solaris.  */
+/* Enable X/Open compliant socket functions that do not require linking
+   with -lxnet on HP-UX 11.11.  */
+#ifndef _HPUX_ALT_XOPEN_SOCKET_API
+# undef _HPUX_ALT_XOPEN_SOCKET_API
+#endif
+/* Identify the host operating system as Minix.
+   This macro does not affect the system headers' behavior.
+   A future release of Autoconf may stop defining this macro.  */
+#ifndef _MINIX
+# undef _MINIX
+#endif
+/* Enable general extensions on NetBSD.
+   Enable NetBSD compatibility extensions on Minix.  */
+#ifndef _NETBSD_SOURCE
+# undef _NETBSD_SOURCE
+#endif
+/* Enable OpenBSD compatibility extensions on NetBSD.
+   Oddly enough, this does nothing on OpenBSD.  */
+#ifndef _OPENBSD_SOURCE
+# undef _OPENBSD_SOURCE
+#endif
+/* Define to 1 if needed for POSIX-compatible behavior.  */
+#ifndef _POSIX_SOURCE
+# undef _POSIX_SOURCE
+#endif
+/* Define to 2 if needed for POSIX-compatible behavior.  */
+#ifndef _POSIX_1_SOURCE
+# undef _POSIX_1_SOURCE
+#endif
+/* Enable POSIX-compatible threading on Solaris.  */
 #ifndef _POSIX_PTHREAD_SEMANTICS
 # undef _POSIX_PTHREAD_SEMANTICS
 #endif
+/* Enable extensions specified by ISO/IEC TS 18661-5:2014.  */
+#ifndef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
+# undef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-1:2014.  */
+#ifndef __STDC_WANT_IEC_60559_BFP_EXT__
+# undef __STDC_WANT_IEC_60559_BFP_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-2:2015.  */
+#ifndef __STDC_WANT_IEC_60559_DFP_EXT__
+# undef __STDC_WANT_IEC_60559_DFP_EXT__
+#endif
+/* Enable extensions specified by C23 Annex F.  */
+#ifndef __STDC_WANT_IEC_60559_EXT__
+# undef __STDC_WANT_IEC_60559_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-4:2015.  */
+#ifndef __STDC_WANT_IEC_60559_FUNCS_EXT__
+# undef __STDC_WANT_IEC_60559_FUNCS_EXT__
+#endif
+/* Enable extensions specified by C23 Annex H and ISO/IEC TS 18661-3:2015.  */
+#ifndef __STDC_WANT_IEC_60559_TYPES_EXT__
+# undef __STDC_WANT_IEC_60559_TYPES_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TR 24731-2:2010.  */
+#ifndef __STDC_WANT_LIB_EXT2__
+# undef __STDC_WANT_LIB_EXT2__
+#endif
+/* Enable extensions specified by ISO/IEC 24747:2009.  */
+#ifndef __STDC_WANT_MATH_SPEC_FUNCS__
+# undef __STDC_WANT_MATH_SPEC_FUNCS__
+#endif
 /* Enable extensions on HP NonStop.  */
 #ifndef _TANDEM_SOURCE
 # undef _TANDEM_SOURCE
 #endif
-/* Enable X/Open extensions if necessary.  HP-UX 11.11 defines
-   mbstate_t only if _XOPEN_SOURCE is defined to 500, regardless of
-   whether compiling with -Ae or -D_HPUX_SOURCE=1.  */
+/* Enable X/Open extensions.  Define to 500 only if necessary
+   to make mbstate_t available.  */
 #ifndef _XOPEN_SOURCE
 # undef _XOPEN_SOURCE
 #endif
-/* Enable general extensions on Solaris.  */
-#ifndef __EXTENSIONS__
-# undef __EXTENSIONS__
-#endif
-])
+])dnl
+
+  AC_REQUIRE([AC_CHECK_INCLUDES_DEFAULT])dnl
+  _AC_CHECK_HEADER_ONCE([wchar.h])
+  _AC_CHECK_HEADER_ONCE([minix/config.h])
+
+dnl Defining __EXTENSIONS__ may break the system headers on some systems.
+dnl (FIXME: Which ones?)
   AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
     [ac_cv_safe_to_define___extensions__],
     [AC_COMPILE_IFELSE(
@@ -95,30 +158,57 @@ dnl configure.ac when using autoheader 2.62.
           ]AC_INCLUDES_DEFAULT])],
        [ac_cv_safe_to_define___extensions__=yes],
        [ac_cv_safe_to_define___extensions__=no])])
-  test $ac_cv_safe_to_define___extensions__ = yes &&
-    AC_DEFINE([__EXTENSIONS__])
-  AC_DEFINE([_ALL_SOURCE])
-  AC_DEFINE([_DARWIN_C_SOURCE])
-  AC_DEFINE([_GNU_SOURCE])
-  AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
-  AC_DEFINE([_TANDEM_SOURCE])
+
+dnl HP-UX 11.11 defines mbstate_t only if _XOPEN_SOURCE is defined to
+dnl 500, regardless of whether compiling with -Ae or -D_HPUX_SOURCE=1.
+dnl But defining _XOPEN_SOURCE may turn *off* extensions on platforms
+dnl not covered by turn-on-extensions macros (notably Dragonfly, Free,
+dnl and OpenBSD, which don't have any equivalent of _NETBSD_SOURCE) so
+dnl it should only be defined when necessary.
   AC_CACHE_CHECK([whether _XOPEN_SOURCE should be defined],
     [ac_cv_should_define__xopen_source],
     [ac_cv_should_define__xopen_source=no
-     AC_COMPILE_IFELSE(
-       [AC_LANG_PROGRAM([[
+    AS_IF([test $ac_cv_header_wchar_h = yes],
+      [AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM([[
           #include <wchar.h>
           mbstate_t x;]])],
-       [],
-       [AC_COMPILE_IFELSE(
+        [],
+        [AC_COMPILE_IFELSE(
           [AC_LANG_PROGRAM([[
-             #define _XOPEN_SOURCE 500
-             #include <wchar.h>
-             mbstate_t x;]])],
-          [ac_cv_should_define__xopen_source=yes])])])
-  test $ac_cv_should_define__xopen_source = yes &&
-    AC_DEFINE([_XOPEN_SOURCE], [500])
+            #define _XOPEN_SOURCE 500
+            #include <wchar.h>
+            mbstate_t x;]])],
+          [ac_cv_should_define__xopen_source=yes])])])])
+
+  AC_DEFINE([_ALL_SOURCE])
+  AC_DEFINE([_DARWIN_C_SOURCE])
+  AC_DEFINE([_GNU_SOURCE])
+  AC_DEFINE([_HPUX_ALT_XOPEN_SOCKET_API])
+  AC_DEFINE([_NETBSD_SOURCE])
+  AC_DEFINE([_OPENBSD_SOURCE])
+  AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
+  AC_DEFINE([__STDC_WANT_IEC_60559_ATTRIBS_EXT__])
+  AC_DEFINE([__STDC_WANT_IEC_60559_BFP_EXT__])
+  AC_DEFINE([__STDC_WANT_IEC_60559_DFP_EXT__])
+  AC_DEFINE([__STDC_WANT_IEC_60559_EXT__])
+  AC_DEFINE([__STDC_WANT_IEC_60559_FUNCS_EXT__])
+  AC_DEFINE([__STDC_WANT_IEC_60559_TYPES_EXT__])
+  AC_DEFINE([__STDC_WANT_LIB_EXT2__])
+  AC_DEFINE([__STDC_WANT_MATH_SPEC_FUNCS__])
+  AC_DEFINE([_TANDEM_SOURCE])
+  AS_IF([test $ac_cv_header_minix_config_h = yes],
+    [MINIX=yes
+    AC_DEFINE([_MINIX])
+    AC_DEFINE([_POSIX_SOURCE])
+    AC_DEFINE([_POSIX_1_SOURCE], [2])],
+    [MINIX=])
+  AS_IF([test $ac_cv_safe_to_define___extensions__ = yes],
+    [AC_DEFINE([__EXTENSIONS__])])
+  AS_IF([test $ac_cv_should_define__xopen_source = yes],
+    [AC_DEFINE([_XOPEN_SOURCE], [500])])
 ])# AC_USE_SYSTEM_EXTENSIONS
+])
 
 # gl_USE_SYSTEM_EXTENSIONS
 # ------------------------
@@ -126,13 +216,17 @@ dnl configure.ac when using autoheader 2.62.
 # typically due to standards-conformance issues.
 AC_DEFUN_ONCE([gl_USE_SYSTEM_EXTENSIONS],
 [
-  dnl Require this macro before AC_USE_SYSTEM_EXTENSIONS.
-  dnl gnulib does not need it. But if it gets required by third-party macros
-  dnl after AC_USE_SYSTEM_EXTENSIONS is required, autoconf 2.62..2.63 emit a
-  dnl warning: "AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS".
-  dnl Note: We can do this only for one of the macros AC_AIX, AC_GNU_SOURCE,
-  dnl AC_MINIX. If people still use AC_AIX or AC_MINIX, they are out of luck.
-  AC_REQUIRE([AC_GNU_SOURCE])
-
   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  dnl On OpenBSD 6.8 with GCC, the include files contain a couple of
+  dnl definitions that are only activated with an explicit -D_ISOC11_SOURCE.
+  dnl That's because this version of GCC (4.2.1) supports the option
+  dnl '-std=gnu99' but not the option '-std=gnu11'.
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    openbsd*)
+      AC_DEFINE([_ISOC11_SOURCE], [1],
+        [Define to enable the declarations of ISO C 11 types and functions.])
+      ;;
+  esac
 ])
diff --git a/gl/m4/extern-inline.m4 b/gl/m4/extern-inline.m4
index c4c5e7f2..c001b1cf 100644
--- a/gl/m4/extern-inline.m4
+++ b/gl/m4/extern-inline.m4
@@ -1,61 +1,121 @@
 dnl 'extern inline' a la ISO C99.
 
-dnl Copyright 2012-2013 Free Software Foundation, Inc.
+dnl Copyright 2012-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_EXTERN_INLINE],
 [
-  AH_VERBATIM([extern_inline],
+  AC_CACHE_CHECK([whether ctype.h defines __header_inline],
+    [gl_cv_have___header_inline],
+    [AC_PREPROC_IFELSE(
+       [AC_LANG_SOURCE([[#include <ctype.h>
+                         #ifndef __header_inline
+                          #error "<ctype.h> does not define __header_inline"
+                         #endif
+                        ]])],
+       [gl_cv_have___header_inline=yes],
+       [gl_cv_have___header_inline=no])])
+  if test "$gl_cv_have___header_inline" = yes; then
+    AC_DEFINE([HAVE___HEADER_INLINE], [1],
+      [Define to 1 if ctype.h defines __header_inline.])
+  fi
+
+  AH_VERBATIM([HAVE___HEADER_INLINE_1],
 [/* Please see the Gnulib manual for how to use these macros.
 
    Suppress extern inline with HP-UX cc, as it appears to be broken; see
-   <http://lists.gnu.org/archive/html/bug-texinfo/2013-02/msg00030.html>.
+   <https://lists.gnu.org/r/bug-texinfo/2013-02/msg00030.html>.
 
    Suppress extern inline with Sun C in standards-conformance mode, as it
    mishandles inline functions that call each other.  E.g., for 'inline void f
    (void) { } inline void g (void) { f (); }', c99 incorrectly complains
    'reference to static identifier "f" in extern inline function'.
-   This bug was observed with Sun C 5.12 SunOS_i386 2011/11/16.
+   This bug was observed with Oracle Developer Studio 12.6
+   (Sun C 5.15 SunOS_sparc 2017/05/30).
+
+   Suppress extern inline (with or without __attribute__ ((__gnu_inline__)))
+   on configurations that mistakenly use 'static inline' to implement
+   functions or macros in standard C headers like <ctype.h>.  For example,
+   if isdigit is mistakenly implemented via a static inline function,
+   a program containing an extern inline function that calls isdigit
+   may not work since the C standard prohibits extern inline functions
+   from calling static functions (ISO C 99 section 6.7.4.(3).
+   This bug is known to occur on:
+
+     OS X 10.8 and earlier; see:
+     https://lists.gnu.org/r/bug-gnulib/2012-12/msg00023.html
+
+     DragonFly; see
+     http://muscles.dragonflybsd.org/bulk/clang-master-potential/20141111_102002/logs/ah-tty-0.3.12.log
 
-   Suppress the use of extern inline on Apple's platforms, as Libc at least
-   through Libc-825.26 (2013-04-09) is incompatible with it; see, e.g.,
-   <http://lists.gnu.org/archive/html/bug-gnulib/2012-12/msg00023.html>.
-   Perhaps Apple will fix this some day.  */
+     FreeBSD; see:
+     https://lists.gnu.org/r/bug-gnulib/2014-07/msg00104.html
+
+   OS X 10.9 has a macro __header_inline indicating the bug is fixed for C and
+   for clang but remains for g++; see <https://trac.macports.org/ticket/41033>.
+   Assume DragonFly and FreeBSD will be similar.
+
+   GCC 4.3 and above with -std=c99 or -std=gnu99 implements ISO C99
+   inline semantics, unless -fgnu89-inline is used.  It defines a macro
+   __GNUC_STDC_INLINE__ to indicate this situation or a macro
+   __GNUC_GNU_INLINE__ to indicate the opposite situation.
+   GCC 4.2 with -std=c99 or -std=gnu99 implements the GNU C inline
+   semantics but warns, unless -fgnu89-inline is used:
+     warning: C99 inline functions are not supported; using GNU89
+     warning: to disable this warning use -fgnu89-inline or the gnu_inline function attribute
+   It defines a macro __GNUC_GNU_INLINE__ to indicate this situation.
+ */
+#if (((defined __APPLE__ && defined __MACH__) \
+      || defined __DragonFly__ || defined __FreeBSD__) \
+     && (defined HAVE___HEADER_INLINE \
+         ? (defined __cplusplus && defined __GNUC_STDC_INLINE__ \
+            && ! defined __clang__) \
+         : ((! defined _DONT_USE_CTYPE_INLINE_ \
+             && (defined __GNUC__ || defined __cplusplus)) \
+            || (defined _FORTIFY_SOURCE && 0 < _FORTIFY_SOURCE \
+                && defined __GNUC__ && ! defined __cplusplus))))
+# define _GL_EXTERN_INLINE_STDHEADER_BUG
+#endif
 #if ((__GNUC__ \
       ? defined __GNUC_STDC_INLINE__ && __GNUC_STDC_INLINE__ \
       : (199901L <= __STDC_VERSION__ \
          && !defined __HP_cc \
+         && !defined __PGI \
          && !(defined __SUNPRO_C && __STDC__))) \
-     && !defined __APPLE__)
+     && !defined _GL_EXTERN_INLINE_STDHEADER_BUG)
 # define _GL_INLINE inline
 # define _GL_EXTERN_INLINE extern inline
+# define _GL_EXTERN_INLINE_IN_USE
 #elif (2 < __GNUC__ + (7 <= __GNUC_MINOR__) && !defined __STRICT_ANSI__ \
-       && !defined __APPLE__)
-# if __GNUC_GNU_INLINE__
+       && !defined _GL_EXTERN_INLINE_STDHEADER_BUG)
+# if defined __GNUC_GNU_INLINE__ && __GNUC_GNU_INLINE__
    /* __gnu_inline__ suppresses a GCC 4.2 diagnostic.  */
 #  define _GL_INLINE extern inline __attribute__ ((__gnu_inline__))
 # else
 #  define _GL_INLINE extern inline
 # endif
 # define _GL_EXTERN_INLINE extern
+# define _GL_EXTERN_INLINE_IN_USE
 #else
-# define _GL_INLINE static _GL_UNUSED
-# define _GL_EXTERN_INLINE static _GL_UNUSED
+# define _GL_INLINE _GL_UNUSED static
+# define _GL_EXTERN_INLINE _GL_UNUSED static
 #endif
 
-#if 4 < __GNUC__ + (6 <= __GNUC_MINOR__)
+/* In GCC 4.6 (inclusive) to 5.1 (exclusive),
+   suppress bogus "no previous prototype for 'FOO'"
+   and "no previous declaration for 'FOO'" diagnostics,
+   when FOO is an inline function in the header; see
+   <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54113> and
+   <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63877>.  */
+#if __GNUC__ == 4 && 6 <= __GNUC_MINOR__
 # if defined __GNUC_STDC_INLINE__ && __GNUC_STDC_INLINE__
 #  define _GL_INLINE_HEADER_CONST_PRAGMA
 # else
 #  define _GL_INLINE_HEADER_CONST_PRAGMA \
      _Pragma ("GCC diagnostic ignored \"-Wsuggest-attribute=const\"")
 # endif
-  /* Suppress GCC's bogus "no previous prototype for 'FOO'"
-     and "no previous declaration for 'FOO'"  diagnostics,
-     when FOO is an inline function in the header; see
-     <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54113>.  */
 # define _GL_INLINE_HEADER_BEGIN \
     _Pragma ("GCC diagnostic push") \
     _Pragma ("GCC diagnostic ignored \"-Wmissing-prototypes\"") \
diff --git a/gl/m4/fcntl-o.m4 b/gl/m4/fcntl-o.m4
index 87cc4bd2..59d558bd 100644
--- a/gl/m4/fcntl-o.m4
+++ b/gl/m4/fcntl-o.m4
@@ -1,23 +1,22 @@
-# fcntl-o.m4 serial 4
-dnl Copyright (C) 2006, 2009-2013 Free Software Foundation, Inc.
+# fcntl-o.m4 serial 7
+dnl Copyright (C) 2006, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl Written by Paul Eggert.
 
+AC_PREREQ([2.60])
+
 # Test whether the flags O_NOATIME and O_NOFOLLOW actually work.
 # Define HAVE_WORKING_O_NOATIME to 1 if O_NOATIME works, or to 0 otherwise.
 # Define HAVE_WORKING_O_NOFOLLOW to 1 if O_NOFOLLOW works, or to 0 otherwise.
 AC_DEFUN([gl_FCNTL_O_FLAGS],
 [
   dnl Persuade glibc <fcntl.h> to define O_NOATIME and O_NOFOLLOW.
-  dnl AC_USE_SYSTEM_EXTENSIONS was introduced in autoconf 2.60 and obsoletes
-  dnl AC_GNU_SOURCE.
-  m4_ifdef([AC_USE_SYSTEM_EXTENSIONS],
-    [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])],
-    [AC_REQUIRE([AC_GNU_SOURCE])])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
   AC_CHECK_HEADERS_ONCE([unistd.h])
   AC_CHECK_FUNCS_ONCE([symlink])
   AC_CACHE_CHECK([for working fcntl.h], [gl_cv_header_working_fcntl_h],
@@ -33,6 +32,7 @@ AC_DEFUN([gl_FCNTL_O_FLAGS],
            # defined sleep(n) _sleep ((n) * 1000)
            #endif
            #include <fcntl.h>
+           ]GL_MDA_DEFINES[
            #ifndef O_NOATIME
             #define O_NOATIME 0
            #endif
@@ -116,7 +116,13 @@ AC_DEFUN([gl_FCNTL_O_FLAGS],
         68) gl_cv_header_working_fcntl_h='no (bad O_NOATIME, O_NOFOLLOW)';; #(
          *) gl_cv_header_working_fcntl_h='no';;
         esac],
-       [gl_cv_header_working_fcntl_h=cross-compiling])])
+       [case "$host_os" in
+                  # Guess 'no' on native Windows.
+          mingw*) gl_cv_header_working_fcntl_h='no' ;;
+          *)      gl_cv_header_working_fcntl_h=cross-compiling ;;
+        esac
+       ])
+    ])
 
   case $gl_cv_header_working_fcntl_h in #(
   *O_NOATIME* | no | cross-compiling) ac_val=0;; #(
diff --git a/gl/m4/fcntl.m4 b/gl/m4/fcntl.m4
new file mode 100644
index 00000000..524a99af
--- /dev/null
+++ b/gl/m4/fcntl.m4
@@ -0,0 +1,151 @@
+# fcntl.m4 serial 11
+dnl Copyright (C) 2009-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# For now, this module ensures that fcntl()
+# - supports F_DUPFD correctly
+# - supports or emulates F_DUPFD_CLOEXEC
+# - supports F_GETFD
+# Still to be ported to mingw:
+# - F_SETFD
+# - F_GETFL, F_SETFL
+# - F_GETOWN, F_SETOWN
+# - F_GETLK, F_SETLK, F_SETLKW
+AC_DEFUN([gl_FUNC_FCNTL],
+[
+  dnl Persuade glibc to expose F_DUPFD_CLOEXEC.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CHECK_FUNCS_ONCE([fcntl])
+  if test $ac_cv_func_fcntl = no; then
+    gl_REPLACE_FCNTL
+  else
+    dnl cygwin 1.5.x F_DUPFD has wrong errno, and allows negative target
+    dnl haiku alpha 2 F_DUPFD has wrong errno
+    AC_CACHE_CHECK([whether fcntl handles F_DUPFD correctly],
+      [gl_cv_func_fcntl_f_dupfd_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <errno.h>
+              #include <fcntl.h>
+              #include <limits.h>
+              #include <sys/resource.h>
+              #include <unistd.h>
+              ]GL_MDA_DEFINES[
+              #ifndef RLIM_SAVED_CUR
+              # define RLIM_SAVED_CUR RLIM_INFINITY
+              #endif
+              #ifndef RLIM_SAVED_MAX
+              # define RLIM_SAVED_MAX RLIM_INFINITY
+              #endif
+            ]],
+            [[int result = 0;
+              int bad_fd = INT_MAX;
+              struct rlimit rlim;
+              if (getrlimit (RLIMIT_NOFILE, &rlim) == 0
+                  && 0 <= rlim.rlim_cur && rlim.rlim_cur <= INT_MAX
+                  && rlim.rlim_cur != RLIM_INFINITY
+                  && rlim.rlim_cur != RLIM_SAVED_MAX
+                  && rlim.rlim_cur != RLIM_SAVED_CUR)
+                bad_fd = rlim.rlim_cur;
+              if (fcntl (0, F_DUPFD, -1) != -1) result |= 1;
+              if (errno != EINVAL) result |= 2;
+              if (fcntl (0, F_DUPFD, bad_fd) != -1) result |= 4;
+              if (errno != EINVAL) result |= 8;
+              /* On OS/2 kLIBC, F_DUPFD does not work on a directory fd */
+              {
+                int fd;
+                fd = open (".", O_RDONLY);
+                if (fd == -1)
+                  result |= 16;
+                else if (fcntl (fd, F_DUPFD, STDERR_FILENO + 1) == -1)
+                  result |= 32;
+
+                close (fd);
+              }
+              return result;]])],
+         [gl_cv_func_fcntl_f_dupfd_works=yes],
+         [gl_cv_func_fcntl_f_dupfd_works=no],
+         [case $host_os in
+            aix* | cygwin* | haiku*)
+               gl_cv_func_fcntl_f_dupfd_works="guessing no" ;;
+            *) gl_cv_func_fcntl_f_dupfd_works="guessing yes" ;;
+          esac])])
+    case $gl_cv_func_fcntl_f_dupfd_works in
+      *yes) ;;
+      *) gl_REPLACE_FCNTL
+        AC_DEFINE([FCNTL_DUPFD_BUGGY], [1], [Define this to 1 if F_DUPFD
+          behavior does not match POSIX]) ;;
+    esac
+
+    dnl Many systems lack F_DUPFD_CLOEXEC.
+    dnl NetBSD 9.0 declares F_DUPFD_CLOEXEC but it works only like F_DUPFD.
+    AC_CACHE_CHECK([whether fcntl understands F_DUPFD_CLOEXEC],
+      [gl_cv_func_fcntl_f_dupfd_cloexec],
+      [AC_RUN_IFELSE(
+         [AC_LANG_SOURCE(
+            [[#include <fcntl.h>
+              #include <unistd.h>
+              int main (int argc, char *argv[])
+              {
+                if (argc == 1)
+                  /* parent process */
+                  {
+                    if (fcntl (1, F_DUPFD_CLOEXEC, 10) < 0)
+                      return 1;
+                    return execl ("./conftest", "./conftest", "child", NULL);
+                  }
+                else
+                  /* child process */
+                  return (fcntl (10, F_GETFL) < 0 ? 0 : 42);
+              }
+            ]])
+         ],
+         [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+#ifdef __linux__
+/* The Linux kernel only added F_DUPFD_CLOEXEC in 2.6.24, so we always replace
+   it to support the semantics on older kernels that failed with EINVAL.  */
+choke me
+#endif
+           ]])],
+           [gl_cv_func_fcntl_f_dupfd_cloexec=yes],
+           [gl_cv_func_fcntl_f_dupfd_cloexec="needs runtime check"])
+         ],
+         [gl_cv_func_fcntl_f_dupfd_cloexec=no],
+         [case "$host_os" in
+                     # Guess no on NetBSD.
+            netbsd*) gl_cv_func_fcntl_f_dupfd_cloexec="guessing no" ;;
+            *)       gl_cv_func_fcntl_f_dupfd_cloexec="$gl_cross_guess_normal" ;;
+          esac
+         ])
+      ])
+    case "$gl_cv_func_fcntl_f_dupfd_cloexec" in
+      *yes) ;;
+      *)    gl_REPLACE_FCNTL
+            dnl No witness macro needed for this bug.
+            ;;
+    esac
+  fi
+  dnl Replace fcntl() for supporting the gnulib-defined fchdir() function,
+  dnl to keep fchdir's bookkeeping up-to-date.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    gl_TEST_FCHDIR
+    if test $HAVE_FCHDIR = 0; then
+      gl_REPLACE_FCNTL
+    fi
+  ])
+])
+
+AC_DEFUN([gl_REPLACE_FCNTL],
+[
+  AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([fcntl])
+  if test $ac_cv_func_fcntl = no; then
+    HAVE_FCNTL=0
+  else
+    REPLACE_FCNTL=1
+  fi
+])
diff --git a/gl/m4/fcntl_h.m4 b/gl/m4/fcntl_h.m4
new file mode 100644
index 00000000..68f4e648
--- /dev/null
+++ b/gl/m4/fcntl_h.m4
@@ -0,0 +1,70 @@
+# serial 20
+# Configure fcntl.h.
+dnl Copyright (C) 2006-2007, 2009-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Paul Eggert.
+
+AC_DEFUN_ONCE([gl_FCNTL_H],
+[
+  AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
+  AC_REQUIRE([gl_FCNTL_O_FLAGS])
+  gl_NEXT_HEADERS([fcntl.h])
+
+  dnl Ensure the type pid_t gets defined.
+  AC_REQUIRE([AC_TYPE_PID_T])
+
+  dnl Ensure the type mode_t gets defined.
+  AC_REQUIRE([AC_TYPE_MODE_T])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use, if it is not common
+  dnl enough to be declared everywhere.
+  gl_WARN_ON_USE_PREPARE([[#include <fcntl.h>
+    ]], [fcntl openat])
+])
+
+# gl_FCNTL_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
+AC_DEFUN([gl_FCNTL_MODULE_INDICATOR],
+[
+  dnl Ensure to expand the default settings once only.
+  gl_FCNTL_H_REQUIRE_DEFAULTS
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_FCNTL_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_FCNTL_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CREAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FCNTL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_NONBLOCKING])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_OPEN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_OPENAT])
+    dnl Support Microsoft deprecated alias function names by default.
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_CREAT], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_OPEN], [1])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_FCNTL_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
+])
+
+AC_DEFUN([gl_FCNTL_H_DEFAULTS],
+[
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_FCNTL=1;          AC_SUBST([HAVE_FCNTL])
+  HAVE_OPENAT=1;         AC_SUBST([HAVE_OPENAT])
+  REPLACE_CREAT=0;       AC_SUBST([REPLACE_CREAT])
+  REPLACE_FCNTL=0;       AC_SUBST([REPLACE_FCNTL])
+  REPLACE_OPEN=0;        AC_SUBST([REPLACE_OPEN])
+  REPLACE_OPENAT=0;      AC_SUBST([REPLACE_OPENAT])
+])
diff --git a/gl/m4/fflush.m4 b/gl/m4/fflush.m4
new file mode 100644
index 00000000..3e3c8903
--- /dev/null
+++ b/gl/m4/fflush.m4
@@ -0,0 +1,100 @@
+# fflush.m4 serial 18
+
+# Copyright (C) 2007-2023 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl From Eric Blake
+
+dnl Find out how to obey POSIX semantics of fflush(stdin) discarding
+dnl unread input on seekable streams, rather than C99 undefined semantics.
+
+AC_DEFUN([gl_FUNC_FFLUSH],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  gl_FUNC_FFLUSH_STDIN
+  case "$gl_cv_func_fflush_stdin" in
+    *yes) ;;
+    *) REPLACE_FFLUSH=1 ;;
+  esac
+])
+
+dnl Determine whether fflush works on input streams.
+dnl Sets gl_cv_func_fflush_stdin.
+
+AC_DEFUN([gl_FUNC_FFLUSH_STDIN],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+  AC_CACHE_CHECK([whether fflush works on input streams],
+    [gl_cv_func_fflush_stdin],
+    [echo hello world > conftest.txt
+     AC_RUN_IFELSE([AC_LANG_PROGRAM(
+       [[
+#include <stdio.h>
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#else /* on Windows with MSVC */
+# include <io.h>
+#endif
+       ]GL_MDA_DEFINES],
+       [[FILE *f = fopen ("conftest.txt", "r");
+         char buffer[10];
+         int fd;
+         int c;
+         if (f == NULL)
+           return 1;
+         fd = fileno (f);
+         if (fd < 0 || fread (buffer, 1, 5, f) != 5)
+           { fclose (f); return 2; }
+         /* For deterministic results, ensure f read a bigger buffer.  */
+         if (lseek (fd, 0, SEEK_CUR) == 5)
+           { fclose (f); return 3; }
+         /* POSIX requires fflush-fseek to set file offset of fd.  This fails
+            on BSD systems and on mingw.  */
+         if (fflush (f) != 0 || fseek (f, 0, SEEK_CUR) != 0)
+           { fclose (f); return 4; }
+         if (lseek (fd, 0, SEEK_CUR) != 5)
+           { fclose (f); return 5; }
+         /* Verify behaviour of fflush after ungetc. See
+            <https://www.opengroup.org/austin/aardvark/latest/xshbug3.txt>  */
+         /* Verify behaviour of fflush after a backup ungetc.  This fails on
+            mingw.  */
+         c = fgetc (f);
+         ungetc (c, f);
+         fflush (f);
+         if (fgetc (f) != c)
+           { fclose (f); return 6; }
+         /* Verify behaviour of fflush after a non-backup ungetc.  This fails
+            on glibc 2.8 and on BSD systems.  */
+         c = fgetc (f);
+         ungetc ('@', f);
+         fflush (f);
+         if (fgetc (f) != c)
+           { fclose (f); return 7; }
+         fclose (f);
+         return 0;
+       ]])],
+       [gl_cv_func_fflush_stdin=yes],
+       [gl_cv_func_fflush_stdin=no],
+       [case "$host_os" in
+                  # Guess no on native Windows.
+          mingw*) gl_cv_func_fflush_stdin="guessing no" ;;
+          *)      gl_cv_func_fflush_stdin=cross ;;
+        esac
+       ])
+     rm conftest.txt
+    ])
+  case "$gl_cv_func_fflush_stdin" in
+    *yes) gl_func_fflush_stdin=1 ;;
+    *no)  gl_func_fflush_stdin=0 ;;
+    *)    gl_func_fflush_stdin='(-1)' ;;
+  esac
+  AC_DEFINE_UNQUOTED([FUNC_FFLUSH_STDIN], [$gl_func_fflush_stdin],
+    [Define to 1 if fflush is known to work on stdin as per POSIX.1-2008,
+     0 if fflush is known to not work, -1 if unknown.])
+])
+
+# Prerequisites of lib/fflush.c.
+AC_DEFUN([gl_PREREQ_FFLUSH], [:])
diff --git a/gl/m4/float_h.m4 b/gl/m4/float_h.m4
index 397f2d1f..2f0c9c4e 100644
--- a/gl/m4/float_h.m4
+++ b/gl/m4/float_h.m4
@@ -1,5 +1,5 @@
-# float_h.m4 serial 9
-dnl Copyright (C) 2007, 2009-2013 Free Software Foundation, Inc.
+# float_h.m4 serial 13
+dnl Copyright (C) 2007, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -8,42 +8,46 @@ AC_DEFUN([gl_FLOAT_H],
 [
   AC_REQUIRE([AC_PROG_CC])
   AC_REQUIRE([AC_CANONICAL_HOST])
-  FLOAT_H=
+  GL_GENERATE_FLOAT_H=false
   REPLACE_FLOAT_LDBL=0
   case "$host_os" in
     aix* | beos* | openbsd* | mirbsd* | irix*)
-      FLOAT_H=float.h
+      GL_GENERATE_FLOAT_H=true
       ;;
-    freebsd*)
+    freebsd* | dragonfly*)
       case "$host_cpu" in
 changequote(,)dnl
         i[34567]86 )
 changequote([,])dnl
-          FLOAT_H=float.h
+          GL_GENERATE_FLOAT_H=true
           ;;
         x86_64 )
           # On x86_64 systems, the C compiler may still be generating
           # 32-bit code.
-          AC_EGREP_CPP([yes],
-            [#if defined __LP64__ || defined __x86_64__ || defined __amd64__
-             yes
-             #endif],
+          AC_COMPILE_IFELSE(
+            [AC_LANG_SOURCE(
+               [[#if defined __LP64__ || defined __x86_64__ || defined __amd64__
+                  int ok;
+                 #else
+                  error fail
+                 #endif
+               ]])],
             [],
-            [FLOAT_H=float.h])
+            [GL_GENERATE_FLOAT_H=true])
           ;;
       esac
       ;;
     linux*)
       case "$host_cpu" in
         powerpc*)
-          FLOAT_H=float.h
+          GL_GENERATE_FLOAT_H=true
           ;;
       esac
       ;;
   esac
   case "$host_os" in
-    aix* | freebsd* | linux*)
-      if test -n "$FLOAT_H"; then
+    aix* | freebsd* | dragonfly* | linux*)
+      if $GL_GENERATE_FLOAT_H; then
         REPLACE_FLOAT_LDBL=1
       fi
       ;;
@@ -69,14 +73,20 @@ int main ()
         [gl_cv_func_itold_works=no],
         [case "$host" in
            sparc*-*-linux*)
-             AC_EGREP_CPP([yes],
-               [#if defined __LP64__ || defined __arch64__
-                yes
-                #endif],
+             AC_COMPILE_IFELSE(
+               [AC_LANG_SOURCE(
+                 [[#if defined __LP64__ || defined __arch64__
+                    int ok;
+                   #else
+                    error fail
+                   #endif
+                 ]])],
                [gl_cv_func_itold_works="guessing no"],
                [gl_cv_func_itold_works="guessing yes"])
              ;;
-           *) gl_cv_func_itold_works="guessing yes" ;;
+                   # Guess yes on native Windows.
+           mingw*) gl_cv_func_itold_works="guessing yes" ;;
+           *)      gl_cv_func_itold_works="guessing yes" ;;
          esac
         ])
     ])
@@ -85,14 +95,12 @@ int main ()
       REPLACE_ITOLD=1
       dnl We add the workaround to <float.h> but also to <math.h>,
       dnl to increase the chances that the fix function gets pulled in.
-      FLOAT_H=float.h
+      GL_GENERATE_FLOAT_H=true
       ;;
   esac
 
-  if test -n "$FLOAT_H"; then
+  if $GL_GENERATE_FLOAT_H; then
     gl_NEXT_HEADERS([float.h])
   fi
-  AC_SUBST([FLOAT_H])
-  AM_CONDITIONAL([GL_GENERATE_FLOAT_H], [test -n "$FLOAT_H"])
   AC_SUBST([REPLACE_ITOLD])
 ])
diff --git a/gl/m4/floorf.m4 b/gl/m4/floorf.m4
index c892ff9c..c49ffa6b 100644
--- a/gl/m4/floorf.m4
+++ b/gl/m4/floorf.m4
@@ -1,5 +1,5 @@
-# floorf.m4 serial 13
-dnl Copyright (C) 2007, 2009-2013 Free Software Foundation, Inc.
+# floorf.m4 serial 18
+dnl Copyright (C) 2007, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -39,7 +39,7 @@ AC_DEFUN([gl_FUNC_FLOORF],
 static float dummy (float f) { return 0; }
 int main (int argc, char *argv[])
 {
-  float (*my_floorf) (float) = argc ? floorf : dummy;
+  float (* volatile my_floorf) (float) = argc ? floorf : dummy;
   /* Test whether floorf (-0.0f) is -0.0f.  */
   if (signbitf (minus_zerof) && !signbitf (my_floorf (minus_zerof)))
     return 1;
@@ -49,10 +49,14 @@ int main (int argc, char *argv[])
               [gl_cv_func_floorf_ieee=yes],
               [gl_cv_func_floorf_ieee=no],
               [case "$host_os" in
-                         # Guess yes on glibc systems.
-                 *-gnu*) gl_cv_func_floorf_ieee="guessing yes" ;;
-                         # If we don't know, assume the worst.
-                 *)      gl_cv_func_floorf_ieee="guessing no" ;;
+                                # Guess yes on glibc systems.
+                 *-gnu* | gnu*) gl_cv_func_floorf_ieee="guessing yes" ;;
+                                # Guess yes on musl systems.
+                 *-musl*)       gl_cv_func_floorf_ieee="guessing yes" ;;
+                                # Guess yes on native Windows.
+                 mingw*)        gl_cv_func_floorf_ieee="guessing yes" ;;
+                                # If we don't know, obey --enable-cross-guesses.
+                 *)             gl_cv_func_floorf_ieee="$gl_cross_guess_normal" ;;
                esac
               ])
             LIBS="$save_LIBS"
diff --git a/gl/m4/fopen.m4 b/gl/m4/fopen.m4
new file mode 100644
index 00000000..9c39ff72
--- /dev/null
+++ b/gl/m4/fopen.m4
@@ -0,0 +1,149 @@
+# fopen.m4 serial 13
+dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FOPEN],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw* | pw*)
+      dnl Replace fopen, for handling of "/dev/null".
+      REPLACE_FOPEN=1
+      dnl fopen on mingw also has the trailing slash bug.
+      gl_cv_func_fopen_slash="guessing no"
+      ;;
+    *)
+      dnl fopen("foo/", "w") should not create a file when the file name has a
+      dnl trailing slash.
+      AC_CACHE_CHECK([whether fopen recognizes a trailing slash],
+        [gl_cv_func_fopen_slash],
+        [
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+#include <stddef.h>
+#include <stdio.h>
+int main ()
+{
+  FILE *fp = fopen ("conftest.sl/", "w");
+  int result = (fp != NULL);
+  if (fp != NULL)
+    fclose (fp);
+  return result;
+}]])],
+            [gl_cv_func_fopen_slash=yes],
+            [gl_cv_func_fopen_slash=no],
+            [
+changequote(,)dnl
+             case "$host_os" in
+               aix* | hpux* | solaris2.[0-9] | solaris2.[0-9].*)
+                 gl_cv_func_fopen_slash="guessing no" ;;
+               *)
+                 gl_cv_func_fopen_slash="guessing yes" ;;
+             esac
+changequote([,])dnl
+            ])
+          rm -f conftest.sl
+        ])
+      ;;
+  esac
+  case "$gl_cv_func_fopen_slash" in
+    *no)
+      AC_DEFINE([FOPEN_TRAILING_SLASH_BUG], [1],
+        [Define to 1 if fopen() fails to recognize a trailing slash.])
+      REPLACE_FOPEN=1
+      ;;
+  esac
+])
+
+AC_DEFUN([gl_FUNC_FOPEN_GNU],
+[
+  AC_REQUIRE([gl_FUNC_FOPEN])
+  AC_CACHE_CHECK([whether fopen supports the mode character 'x'],
+    [gl_cv_func_fopen_mode_x],
+    [rm -f conftest.x
+     AC_RUN_IFELSE(
+       [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <errno.h>
+int main ()
+{
+  FILE *fp;
+  fp = fopen ("conftest.x", "w");
+  fclose (fp);
+  fp = fopen ("conftest.x", "wx");
+  if (fp != NULL)
+    /* 'x' ignored */
+    return 1;
+  else if (errno == EEXIST)
+    return 0;
+  else
+    /* 'x' rejected */
+    return 2;
+}]])],
+       [gl_cv_func_fopen_mode_x=yes],
+       [gl_cv_func_fopen_mode_x=no],
+       [case "$host_os" in
+          # Guess yes on glibc and musl systems.
+          linux*-gnu* | gnu* | kfreebsd*-gnu | *-musl*)
+            gl_cv_func_fopen_mode_x="guessing yes" ;;
+          # If we don't know, obey --enable-cross-guesses.
+          *)
+            gl_cv_func_fopen_mode_x="$gl_cross_guess_normal" ;;
+        esac
+       ])
+     rm -f conftest.x
+    ])
+  AC_CACHE_CHECK([whether fopen supports the mode character 'e'],
+    [gl_cv_func_fopen_mode_e],
+    [echo foo > conftest.x
+     AC_RUN_IFELSE(
+       [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <errno.h>
+#include <fcntl.h>
+]GL_MDA_DEFINES[
+int main ()
+{
+  FILE *fp = fopen ("conftest.x", "re");
+  if (fp != NULL)
+    {
+      if (fcntl (fileno (fp), F_GETFD) & FD_CLOEXEC)
+        return 0;
+      else
+        /* 'e' ignored */
+        return 1;
+    }
+  else
+    /* 'e' rejected */
+    return 2;
+}]])],
+       [gl_cv_func_fopen_mode_e=yes],
+       [gl_cv_func_fopen_mode_e=no],
+       [case "$host_os" in
+          # Guess yes on glibc and musl systems.
+          linux*-gnu* | gnu* | kfreebsd*-gnu | *-musl*)
+            gl_cv_func_fopen_mode_e="guessing yes" ;;
+          # Guess no on native Windows.
+          mingw*)
+            gl_cv_func_fopen_mode_e="guessing no" ;;
+          # If we don't know, obey --enable-cross-guesses.
+          *)
+            gl_cv_func_fopen_mode_e="$gl_cross_guess_normal" ;;
+        esac
+       ])
+     rm -f conftest.x
+    ])
+  REPLACE_FOPEN_FOR_FOPEN_GNU="$REPLACE_FOPEN"
+  case "$gl_cv_func_fopen_mode_x" in
+    *no) REPLACE_FOPEN_FOR_FOPEN_GNU=1 ;;
+  esac
+  case "$gl_cv_func_fopen_mode_e" in
+    *no) REPLACE_FOPEN_FOR_FOPEN_GNU=1 ;;
+  esac
+])
+
+# Prerequisites of lib/fopen.c.
+AC_DEFUN([gl_PREREQ_FOPEN], [:])
diff --git a/gl/m4/fpurge.m4 b/gl/m4/fpurge.m4
new file mode 100644
index 00000000..b365409d
--- /dev/null
+++ b/gl/m4/fpurge.m4
@@ -0,0 +1,73 @@
+# fpurge.m4 serial 12
+dnl Copyright (C) 2007, 2009-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FPURGE],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
+  AC_CHECK_FUNCS_ONCE([fpurge])
+  AC_CHECK_FUNCS_ONCE([__fpurge])
+  AC_CHECK_DECLS([fpurge], , , [[#include <stdio.h>]])
+  if test "x$ac_cv_func_fpurge" = xyes; then
+    HAVE_FPURGE=1
+    # Detect BSD bug.  Only cygwin 1.7 and musl are known to be immune.
+    AC_CACHE_CHECK([whether fpurge works], [gl_cv_func_fpurge_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <stdio.h>
+]],
+            [[FILE *f = fopen ("conftest.txt", "w+");
+              if (!f)
+                return 1;
+              if (fputc ('a', f) != 'a')
+                { fclose (f); return 2; }
+              rewind (f);
+              if (fgetc (f) != 'a')
+                { fclose (f); return 3; }
+              if (fgetc (f) != EOF)
+                { fclose (f); return 4; }
+              if (fpurge (f) != 0)
+                { fclose (f); return 5; }
+              if (putc ('b', f) != 'b')
+                { fclose (f); return 6; }
+              if (fclose (f) != 0)
+                return 7;
+              if ((f = fopen ("conftest.txt", "r")) == NULL)
+                return 8;
+              if (fgetc (f) != 'a')
+                { fclose (f); return 9; }
+              if (fgetc (f) != 'b')
+                { fclose (f); return 10; }
+              if (fgetc (f) != EOF)
+                { fclose (f); return 11; }
+              if (fclose (f) != 0)
+                return 12;
+              if (remove ("conftest.txt") != 0)
+                return 13;
+              return 0;
+            ]])],
+         [gl_cv_func_fpurge_works=yes],
+         [gl_cv_func_fpurge_works=no],
+         [case "$host_os" in
+                     # Guess yes on musl systems.
+            *-musl*) gl_cv_func_fpurge_works="guessing yes" ;;
+                     # Otherwise obey --enable-cross-guesses.
+            *)       gl_cv_func_fpurge_works="$gl_cross_guess_normal" ;;
+          esac
+         ])
+      ])
+    case "$gl_cv_func_fpurge_works" in
+      *yes) ;;
+      *) REPLACE_FPURGE=1 ;;
+    esac
+  else
+    HAVE_FPURGE=0
+  fi
+  if test "x$ac_cv_have_decl_fpurge" = xno; then
+    HAVE_DECL_FPURGE=0
+  fi
+])
diff --git a/gl/m4/freading.m4 b/gl/m4/freading.m4
new file mode 100644
index 00000000..35333369
--- /dev/null
+++ b/gl/m4/freading.m4
@@ -0,0 +1,11 @@
+# freading.m4 serial 2
+dnl Copyright (C) 2007, 2009-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FREADING],
+[
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
+  AC_CHECK_FUNCS_ONCE([__freading])
+])
diff --git a/gl/m4/free.m4 b/gl/m4/free.m4
new file mode 100644
index 00000000..0389dea3
--- /dev/null
+++ b/gl/m4/free.m4
@@ -0,0 +1,52 @@
+# free.m4 serial 6
+# Copyright (C) 2003-2005, 2009-2023 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Written by Paul Eggert and Bruno Haible.
+
+AC_DEFUN([gl_FUNC_FREE],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+
+  dnl In the next release of POSIX, free must preserve errno.
+  dnl https://www.austingroupbugs.net/view.php?id=385
+  dnl https://sourceware.org/bugzilla/show_bug.cgi?id=17924
+  dnl So far, we know of three platforms that do this:
+  dnl * glibc >= 2.33, thanks to the fix for this bug:
+  dnl   <https://sourceware.org/bugzilla/show_bug.cgi?id=17924>
+  dnl * OpenBSD >= 4.5, thanks to this commit:
+  dnl   <https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/lib/libc/stdlib/malloc.c.diff?r1=1.100&r2=1.101&f=h>
+  dnl * Solaris, because its malloc() implementation is based on brk(),
+  dnl   not mmap(); hence its free() implementation makes no system calls.
+  dnl For other platforms, you can only be sure if they state it in their
+  dnl documentation, or by code inspection of the free() implementation in libc.
+  AC_CACHE_CHECK([whether free is known to preserve errno],
+    [gl_cv_func_free_preserves_errno],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <stdlib.h>
+          ]],
+          [[#if 2 < __GLIBC__ + (33 <= __GLIBC_MINOR__)
+            #elif defined __OpenBSD__
+            #elif defined __sun
+            #else
+              #error "'free' is not known to preserve errno"
+            #endif
+          ]])],
+       [gl_cv_func_free_preserves_errno=yes],
+       [gl_cv_func_free_preserves_errno=no])
+    ])
+
+  case $gl_cv_func_free_preserves_errno in
+   *yes)
+    AC_DEFINE([HAVE_FREE_POSIX], [1],
+      [Define if the 'free' function is guaranteed to preserve errno.])
+    ;;
+   *) REPLACE_FREE=1 ;;
+  esac
+])
+
+# Prerequisites of lib/free.c.
+AC_DEFUN([gl_PREREQ_FREE], [:])
diff --git a/gl/m4/fseek.m4 b/gl/m4/fseek.m4
new file mode 100644
index 00000000..c5fe688c
--- /dev/null
+++ b/gl/m4/fseek.m4
@@ -0,0 +1,15 @@
+# fseek.m4 serial 4
+dnl Copyright (C) 2007, 2009-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FSEEK],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_FSEEKO])
+  dnl When fseeko needs fixes, fseek needs them too.
+  if test $HAVE_FSEEKO = 0 || test $REPLACE_FSEEKO = 1; then
+    REPLACE_FSEEK=1
+  fi
+])
diff --git a/gl/m4/fseeko.m4 b/gl/m4/fseeko.m4
new file mode 100644
index 00000000..05ee06bc
--- /dev/null
+++ b/gl/m4/fseeko.m4
@@ -0,0 +1,77 @@
+# fseeko.m4 serial 20
+dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FSEEKO],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([gl_STDIN_LARGE_OFFSET])
+  AC_REQUIRE([gl_SYS_TYPES_H])
+  AC_REQUIRE([AC_PROG_CC])
+
+  dnl Persuade glibc <stdio.h> to declare fseeko().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CACHE_CHECK([for fseeko], [gl_cv_func_fseeko],
+    [
+      AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>
+]], [[fseeko (stdin, 0, 0);]])],
+        [gl_cv_func_fseeko=yes], [gl_cv_func_fseeko=no])
+    ])
+
+  AC_CHECK_DECLS_ONCE([fseeko])
+  if test $ac_cv_have_decl_fseeko = no; then
+    HAVE_DECL_FSEEKO=0
+  fi
+
+  if test $gl_cv_func_fseeko = no; then
+    HAVE_FSEEKO=0
+  else
+    if test $WINDOWS_64_BIT_OFF_T = 1; then
+      REPLACE_FSEEKO=1
+    fi
+    if test $gl_cv_var_stdin_large_offset = no; then
+      REPLACE_FSEEKO=1
+    fi
+    m4_ifdef([gl_FUNC_FFLUSH_STDIN], [
+      gl_FUNC_FFLUSH_STDIN
+      case "$gl_cv_func_fflush_stdin" in
+        *yes) ;;
+        *) REPLACE_FSEEKO=1 ;;
+      esac
+    ])
+  fi
+])
+
+dnl Code shared by fseeko and ftello.  Determine if large files are supported,
+dnl but stdin does not start as a large file by default.
+AC_DEFUN([gl_STDIN_LARGE_OFFSET],
+  [
+    AC_CACHE_CHECK([whether stdin defaults to large file offsets],
+      [gl_cv_var_stdin_large_offset],
+      [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>]],
+[[#if defined __SL64 && defined __SCLE /* cygwin */
+  /* Cygwin 1.5.24 and earlier fail to put stdin in 64-bit mode, making
+     fseeko/ftello needlessly fail.  This bug was fixed in 1.5.25, and
+     it is easier to do a version check than building a runtime test.  */
+# include <cygwin/version.h>
+# if CYGWIN_VERSION_DLL_COMBINED < CYGWIN_VERSION_DLL_MAKE_COMBINED (1005, 25)
+  choke me
+# endif
+#endif]])],
+        [gl_cv_var_stdin_large_offset=yes],
+        [gl_cv_var_stdin_large_offset=no])])
+])
+
+# Prerequisites of lib/fseeko.c.
+AC_DEFUN([gl_PREREQ_FSEEKO],
+[
+  dnl Native Windows has the function _fseeki64. mingw hides it in some
+  dnl circumstances, but mingw64 makes it usable again.
+  AC_CHECK_FUNCS([_fseeki64])
+  if test $ac_cv_func__fseeki64 = yes; then
+    AC_CHECK_DECLS([_fseeki64])
+  fi
+])
diff --git a/gl/m4/fstat.m4 b/gl/m4/fstat.m4
new file mode 100644
index 00000000..7cb2edb0
--- /dev/null
+++ b/gl/m4/fstat.m4
@@ -0,0 +1,40 @@
+# fstat.m4 serial 8
+dnl Copyright (C) 2011-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FSTAT],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+
+  case "$host_os" in
+    mingw* | solaris*)
+      dnl On MinGW, the original stat() returns st_atime, st_mtime,
+      dnl st_ctime values that are affected by the time zone.
+      dnl Solaris stat can return a negative tv_nsec.
+      REPLACE_FSTAT=1
+      ;;
+  esac
+
+  dnl Replace fstat() for supporting the gnulib-defined open() on directories.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    gl_TEST_FCHDIR
+    if test $HAVE_FCHDIR = 0; then
+      case "$gl_cv_func_open_directory_works" in
+        *yes) ;;
+        *)
+          REPLACE_FSTAT=1
+          ;;
+      esac
+    fi
+  ])
+])
+
+# Prerequisites of lib/fstat.c and lib/stat-w32.c.
+AC_DEFUN([gl_PREREQ_FSTAT], [
+  AC_REQUIRE([gl_SYS_STAT_H])
+  AC_REQUIRE([gl_PREREQ_STAT_W32])
+  :
+])
diff --git a/gl/m4/fstypename.m4 b/gl/m4/fstypename.m4
index c72ecb80..f65c459f 100644
--- a/gl/m4/fstypename.m4
+++ b/gl/m4/fstypename.m4
@@ -6,7 +6,7 @@ dnl See if struct statfs has the f_fstypename member.
 dnl If so, define HAVE_STRUCT_STATFS_F_FSTYPENAME.
 dnl
 
-# Copyright (C) 1998-1999, 2001, 2004, 2006, 2009-2013 Free Software
+# Copyright (C) 1998-1999, 2001, 2004, 2006, 2009-2023 Free Software
 # Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
diff --git a/gl/m4/fsusage.m4 b/gl/m4/fsusage.m4
index 6277bfa5..88f3ca81 100644
--- a/gl/m4/fsusage.m4
+++ b/gl/m4/fsusage.m4
@@ -1,7 +1,7 @@
-# serial 30
+# serial 35
 # Obtaining file system usage information.
 
-# Copyright (C) 1997-1998, 2000-2001, 2003-2013 Free Software Foundation, Inc.
+# Copyright (C) 1997-1998, 2000-2001, 2003-2023 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -29,27 +29,29 @@ AC_DEFUN([gl_FSUSAGE],
 
 AC_DEFUN([gl_FILE_SYSTEM_USAGE],
 [
-dnl Enable large-file support. This has the effect of changing the size
-dnl of field f_blocks in 'struct statvfs' from 32 bit to 64 bit on
-dnl glibc/Hurd, HP-UX 11, Solaris (32-bit mode). It also changes the size
-dnl of field f_blocks in 'struct statfs' from 32 bit to 64 bit on
-dnl Mac OS X >= 10.5 (32-bit mode).
-AC_REQUIRE([AC_SYS_LARGEFILE])
+  dnl Enable large-file support. This has the effect of changing the size
+  dnl of field f_blocks in 'struct statvfs' from 32 bit to 64 bit on
+  dnl glibc/Hurd, HP-UX 11, Solaris (32-bit mode). It also changes the size
+  dnl of field f_blocks in 'struct statfs' from 32 bit to 64 bit on
+  dnl Mac OS X >= 10.5 (32-bit mode).
+  AC_REQUIRE([AC_SYS_LARGEFILE])
 
-AC_MSG_NOTICE([checking how to get file system space usage])
-ac_fsusage_space=no
+  ac_fsusage_space=no
 
-# Perform only the link test since it seems there are no variants of the
-# statvfs function.  This check is more than just AC_CHECK_FUNCS([statvfs])
-# because that got a false positive on SCO OSR5.  Adding the declaration
-# of a 'struct statvfs' causes this test to fail (as it should) on such
-# systems.  That system is reported to work fine with STAT_STATFS4 which
-# is what it gets when this test fails.
-if test $ac_fsusage_space = no; then
-  # glibc/{Hurd,kFreeBSD}, FreeBSD >= 5.0, NetBSD >= 3.0,
-  # OpenBSD >= 4.4, AIX, HP-UX, IRIX, Solaris, Cygwin, Interix, BeOS.
-  AC_CACHE_CHECK([for statvfs function (SVR4)], [fu_cv_sys_stat_statvfs],
-                 [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>
+  # Perform only the link test since it seems there are no variants of the
+  # statvfs function.  This check is more than just AC_CHECK_FUNCS([statvfs])
+  # because that got a false positive on SCO OSR5.  Adding the declaration
+  # of a 'struct statvfs' causes this test to fail (as it should) on such
+  # systems.  That system is reported to work fine with STAT_STATFS4 which
+  # is what it gets when this test fails.
+  if test $ac_fsusage_space = no; then
+    # glibc/{Hurd,kFreeBSD}, FreeBSD >= 5.0, NetBSD >= 3.0,
+    # OpenBSD >= 4.4, AIX, HP-UX, IRIX, Solaris, Cygwin, Interix, BeOS.
+    AC_CACHE_CHECK([for statvfs function (SVR4)],
+      [fu_cv_sys_stat_statvfs],
+      [AC_LINK_IFELSE(
+         [AC_LANG_PROGRAM([[
+#include <sys/types.h>
 #ifdef __osf__
 "Do not use Tru64's statvfs implementation"
 #endif
@@ -68,45 +70,47 @@ struct statvfs fsd;
 int check_f_blocks_size[sizeof fsd.f_blocks * CHAR_BIT <= 32 ? -1 : 1];
 #endif
 ]],
-                                    [[statvfs (0, &fsd);]])],
-                                 [fu_cv_sys_stat_statvfs=yes],
-                                 [fu_cv_sys_stat_statvfs=no])])
-  if test $fu_cv_sys_stat_statvfs = yes; then
-    ac_fsusage_space=yes
-    # AIX >= 5.2 has statvfs64 that has a wider f_blocks field than statvfs.
-    # glibc, HP-UX, IRIX, Solaris have statvfs64 as well, but on these systems
-    # statvfs with large-file support is already equivalent to statvfs64.
-    AC_CACHE_CHECK([whether to use statvfs64],
-      [fu_cv_sys_stat_statvfs64],
-      [AC_LINK_IFELSE(
-         [AC_LANG_PROGRAM(
-            [[#include <sys/types.h>
-              #include <sys/statvfs.h>
-              struct statvfs64 fsd;
-              int check_f_blocks_larger_in_statvfs64
-                [sizeof (((struct statvfs64 *) 0)->f_blocks)
-                 > sizeof (((struct statvfs *) 0)->f_blocks)
-                 ? 1 : -1];
-            ]],
-            [[statvfs64 (0, &fsd);]])],
-         [fu_cv_sys_stat_statvfs64=yes],
-         [fu_cv_sys_stat_statvfs64=no])
+            [[statvfs (0, &fsd);]])],
+         [fu_cv_sys_stat_statvfs=yes],
+         [fu_cv_sys_stat_statvfs=no])
       ])
-    if test $fu_cv_sys_stat_statvfs64 = yes; then
-      AC_DEFINE([STAT_STATVFS64], [1],
-                [  Define if statvfs64 should be preferred over statvfs.])
-    else
-      AC_DEFINE([STAT_STATVFS], [1],
-                [  Define if there is a function named statvfs.  (SVR4)])
+    if test $fu_cv_sys_stat_statvfs = yes; then
+      ac_fsusage_space=yes
+      # AIX >= 5.2 has statvfs64 that has a wider f_blocks field than statvfs.
+      # glibc, HP-UX, IRIX, Solaris have statvfs64 as well, but on these systems
+      # statvfs with large-file support is already equivalent to statvfs64.
+      AC_CACHE_CHECK([whether to use statvfs64],
+        [fu_cv_sys_stat_statvfs64],
+        [AC_LINK_IFELSE(
+           [AC_LANG_PROGRAM(
+              [[#include <sys/types.h>
+                #include <sys/statvfs.h>
+                struct statvfs64 fsd;
+                int check_f_blocks_larger_in_statvfs64
+                  [sizeof (((struct statvfs64 *) 0)->f_blocks)
+                   > sizeof (((struct statvfs *) 0)->f_blocks)
+                   ? 1 : -1];
+              ]],
+              [[statvfs64 (0, &fsd);]])],
+           [fu_cv_sys_stat_statvfs64=yes],
+           [fu_cv_sys_stat_statvfs64=no])
+        ])
+      if test $fu_cv_sys_stat_statvfs64 = yes; then
+        AC_DEFINE([STAT_STATVFS64], [1],
+          [Define if statvfs64 should be preferred over statvfs.])
+      else
+        AC_DEFINE([STAT_STATVFS], [1],
+          [Define if there is a function named statvfs.  (SVR4)])
+      fi
     fi
   fi
-fi
 
-# Check for this unconditionally so we have a
-# good fallback on glibc/Linux > 2.6 < 2.6.36
-AC_MSG_CHECKING([for two-argument statfs with statfs.f_frsize member])
-AC_CACHE_VAL([fu_cv_sys_stat_statfs2_frsize],
-[AC_RUN_IFELSE([AC_LANG_SOURCE([[
+  # Check for this unconditionally so we have a
+  # good fallback on glibc/Linux > 2.6 < 2.6.36
+  AC_CACHE_CHECK([for two-argument statfs with statfs.f_frsize member],
+    [fu_cv_sys_stat_statfs2_frsize],
+    [AC_RUN_IFELSE(
+       [AC_LANG_SOURCE([[
 #ifdef HAVE_SYS_PARAM_H
 #include <sys/param.h>
 #endif
@@ -119,26 +123,26 @@ AC_CACHE_VAL([fu_cv_sys_stat_statfs2_frsize],
   int
   main ()
   {
-  struct statfs fsd;
-  fsd.f_frsize = 0;
-  return statfs (".", &fsd) != 0;
+    struct statfs fsd;
+    fsd.f_frsize = 0;
+    return statfs (".", &fsd) != 0;
   }]])],
-  [fu_cv_sys_stat_statfs2_frsize=yes],
-  [fu_cv_sys_stat_statfs2_frsize=no],
-  [fu_cv_sys_stat_statfs2_frsize=no])])
-AC_MSG_RESULT([$fu_cv_sys_stat_statfs2_frsize])
-if test $fu_cv_sys_stat_statfs2_frsize = yes; then
+       [fu_cv_sys_stat_statfs2_frsize=yes],
+       [fu_cv_sys_stat_statfs2_frsize=no],
+       [fu_cv_sys_stat_statfs2_frsize=no])
+    ])
+  if test $fu_cv_sys_stat_statfs2_frsize = yes; then
     ac_fsusage_space=yes
     AC_DEFINE([STAT_STATFS2_FRSIZE], [1],
-[  Define if statfs takes 2 args and struct statfs has a field named f_frsize.
-   (glibc/Linux > 2.6)])
-fi
+      [Define if statfs takes 2 args and struct statfs has a field named f_frsize.
+       (glibc/Linux > 2.6)])
+  fi
 
-if test $ac_fsusage_space = no; then
-  # DEC Alpha running OSF/1
-  AC_MSG_CHECKING([for 3-argument statfs function (DEC OSF/1)])
-  AC_CACHE_VAL([fu_cv_sys_stat_statfs3_osf1],
-  [AC_RUN_IFELSE([AC_LANG_SOURCE([[
+  if test $ac_fsusage_space = no; then
+    # DEC Alpha running OSF/1
+    AC_CACHE_CHECK([for 3-argument statfs function (DEC OSF/1)],
+      [fu_cv_sys_stat_statfs3_osf1],
+      [AC_RUN_IFELSE([AC_LANG_SOURCE([[
 #include <sys/param.h>
 #include <sys/types.h>
 #include <sys/mount.h>
@@ -149,28 +153,27 @@ if test $ac_fsusage_space = no; then
     fsd.f_fsize = 0;
     return statfs (".", &fsd, sizeof (struct statfs)) != 0;
   }]])],
-    [fu_cv_sys_stat_statfs3_osf1=yes],
-    [fu_cv_sys_stat_statfs3_osf1=no],
-    [fu_cv_sys_stat_statfs3_osf1=no])])
-  AC_MSG_RESULT([$fu_cv_sys_stat_statfs3_osf1])
-  if test $fu_cv_sys_stat_statfs3_osf1 = yes; then
-    ac_fsusage_space=yes
-    AC_DEFINE([STAT_STATFS3_OSF1], [1],
-              [   Define if  statfs takes 3 args.  (DEC Alpha running OSF/1)])
+         [fu_cv_sys_stat_statfs3_osf1=yes],
+         [fu_cv_sys_stat_statfs3_osf1=no],
+         [fu_cv_sys_stat_statfs3_osf1=no])
+      ])
+    if test $fu_cv_sys_stat_statfs3_osf1 = yes; then
+      ac_fsusage_space=yes
+      AC_DEFINE([STAT_STATFS3_OSF1], [1],
+        [Define if statfs takes 3 args.  (DEC Alpha running OSF/1)])
+    fi
   fi
-fi
 
-if test $ac_fsusage_space = no; then
-  # glibc/Linux, Mac OS X, FreeBSD < 5.0, NetBSD < 3.0, OpenBSD < 4.4.
-  # (glibc/{Hurd,kFreeBSD}, FreeBSD >= 5.0, NetBSD >= 3.0,
-  # OpenBSD >= 4.4, AIX, HP-UX, OSF/1, Cygwin already handled above.)
-  # (On IRIX you need to include <sys/statfs.h>, not only <sys/mount.h> and
-  # <sys/vfs.h>.)
-  # (On Solaris, statfs has 4 arguments.)
-  AC_MSG_CHECKING([for two-argument statfs with statfs.f_bsize dnl
-member (AIX, 4.3BSD)])
-  AC_CACHE_VAL([fu_cv_sys_stat_statfs2_bsize],
-  [AC_RUN_IFELSE([AC_LANG_SOURCE([[
+  if test $ac_fsusage_space = no; then
+    # glibc/Linux, Mac OS X, FreeBSD < 5.0, NetBSD < 3.0, OpenBSD < 4.4.
+    # (glibc/{Hurd,kFreeBSD}, FreeBSD >= 5.0, NetBSD >= 3.0,
+    # OpenBSD >= 4.4, AIX, HP-UX, OSF/1, Cygwin already handled above.)
+    # (On IRIX you need to include <sys/statfs.h>, not only <sys/mount.h> and
+    # <sys/vfs.h>.)
+    # (On Solaris, statfs has 4 arguments.)
+    AC_CACHE_CHECK([for two-argument statfs with statfs.f_bsize member (AIX, 4.3BSD)],
+      [fu_cv_sys_stat_statfs2_bsize],
+      [AC_RUN_IFELSE([AC_LANG_SOURCE([[
 #ifdef HAVE_SYS_PARAM_H
 #include <sys/param.h>
 #endif
@@ -183,88 +186,56 @@ member (AIX, 4.3BSD)])
   int
   main ()
   {
-  struct statfs fsd;
-  fsd.f_bsize = 0;
-  return statfs (".", &fsd) != 0;
+    struct statfs fsd;
+    fsd.f_bsize = 0;
+    return statfs (".", &fsd) != 0;
   }]])],
-    [fu_cv_sys_stat_statfs2_bsize=yes],
-    [fu_cv_sys_stat_statfs2_bsize=no],
-    [fu_cv_sys_stat_statfs2_bsize=no])])
-  AC_MSG_RESULT([$fu_cv_sys_stat_statfs2_bsize])
-  if test $fu_cv_sys_stat_statfs2_bsize = yes; then
-    ac_fsusage_space=yes
-    AC_DEFINE([STAT_STATFS2_BSIZE], [1],
-[  Define if statfs takes 2 args and struct statfs has a field named f_bsize.
-   (4.3BSD, SunOS 4, HP-UX, AIX PS/2)])
+         [fu_cv_sys_stat_statfs2_bsize=yes],
+         [fu_cv_sys_stat_statfs2_bsize=no],
+         [fu_cv_sys_stat_statfs2_bsize=no])
+      ])
+    if test $fu_cv_sys_stat_statfs2_bsize = yes; then
+      ac_fsusage_space=yes
+      AC_DEFINE([STAT_STATFS2_BSIZE], [1],
+        [Define if statfs takes 2 args and struct statfs has a field named f_bsize.
+         (4.3BSD, SunOS 4, HP-UX)])
+    fi
   fi
-fi
 
-if test $ac_fsusage_space = no; then
-  # SVR3
-  # (Solaris already handled above.)
-  AC_MSG_CHECKING([for four-argument statfs (AIX-3.2.5, SVR3)])
-  AC_CACHE_VAL([fu_cv_sys_stat_statfs4],
-  [AC_RUN_IFELSE([AC_LANG_SOURCE([[
+  if test $ac_fsusage_space = no; then
+    # SVR3
+    # (Solaris already handled above.)
+    AC_CACHE_CHECK([for four-argument statfs (SVR3)],
+      [fu_cv_sys_stat_statfs4],
+      [AC_RUN_IFELSE([AC_LANG_SOURCE([[
 #include <sys/types.h>
 #include <sys/statfs.h>
   int
   main ()
   {
-  struct statfs fsd;
-  return statfs (".", &fsd, sizeof fsd, 0) != 0;
-  }]])],
-    [fu_cv_sys_stat_statfs4=yes],
-    [fu_cv_sys_stat_statfs4=no],
-    [fu_cv_sys_stat_statfs4=no])])
-  AC_MSG_RESULT([$fu_cv_sys_stat_statfs4])
-  if test $fu_cv_sys_stat_statfs4 = yes; then
-    ac_fsusage_space=yes
-    AC_DEFINE([STAT_STATFS4], [1],
-      [  Define if statfs takes 4 args.  (SVR3, Dynix, old Irix, old AIX, Dolphin)])
-  fi
-fi
-
-if test $ac_fsusage_space = no; then
-  # 4.4BSD and older NetBSD
-  # (OSF/1 already handled above.)
-  # (On AIX, you need to include <sys/statfs.h>, not only <sys/mount.h>.)
-  # (On Solaris, statfs has 4 arguments and 'struct statfs' is not declared in
-  # <sys/mount.h>.)
-  AC_MSG_CHECKING([for two-argument statfs with statfs.f_fsize dnl
-member (4.4BSD and NetBSD)])
-  AC_CACHE_VAL([fu_cv_sys_stat_statfs2_fsize],
-  [AC_RUN_IFELSE([AC_LANG_SOURCE([[
-#include <sys/types.h>
-#ifdef HAVE_SYS_PARAM_H
-#include <sys/param.h>
-#endif
-#ifdef HAVE_SYS_MOUNT_H
-#include <sys/mount.h>
-#endif
-  int
-  main ()
-  {
-  struct statfs fsd;
-  fsd.f_fsize = 0;
-  return statfs (".", &fsd) != 0;
+    struct statfs fsd;
+    return statfs (".", &fsd, sizeof fsd, 0) != 0;
   }]])],
-    [fu_cv_sys_stat_statfs2_fsize=yes],
-    [fu_cv_sys_stat_statfs2_fsize=no],
-    [fu_cv_sys_stat_statfs2_fsize=no])])
-  AC_MSG_RESULT([$fu_cv_sys_stat_statfs2_fsize])
-  if test $fu_cv_sys_stat_statfs2_fsize = yes; then
-    ac_fsusage_space=yes
-    AC_DEFINE([STAT_STATFS2_FSIZE], [1],
-[  Define if statfs takes 2 args and struct statfs has a field named f_fsize.
-   (4.4BSD, NetBSD)])
+         [fu_cv_sys_stat_statfs4=yes],
+         [fu_cv_sys_stat_statfs4=no],
+         [fu_cv_sys_stat_statfs4=no])
+      ])
+    if test $fu_cv_sys_stat_statfs4 = yes; then
+      ac_fsusage_space=yes
+      AC_DEFINE([STAT_STATFS4], [1],
+        [Define if statfs takes 4 args.  (SVR3, old Irix)])
+    fi
   fi
-fi
 
-if test $ac_fsusage_space = no; then
-  # Ultrix
-  AC_MSG_CHECKING([for two-argument statfs with struct fs_data (Ultrix)])
-  AC_CACHE_VAL([fu_cv_sys_stat_fs_data],
-  [AC_RUN_IFELSE([AC_LANG_SOURCE([[
+  if test $ac_fsusage_space = no; then
+    # 4.4BSD and older NetBSD
+    # (OSF/1 already handled above.)
+    # (On AIX, you need to include <sys/statfs.h>, not only <sys/mount.h>.)
+    # (On Solaris, statfs has 4 arguments and 'struct statfs' is not declared in
+    # <sys/mount.h>.)
+    AC_CACHE_CHECK([for two-argument statfs with statfs.f_fsize member (4.4BSD and NetBSD)],
+      [fu_cv_sys_stat_statfs2_fsize],
+      [AC_RUN_IFELSE([AC_LANG_SOURCE([[
 #include <sys/types.h>
 #ifdef HAVE_SYS_PARAM_H
 #include <sys/param.h>
@@ -272,41 +243,26 @@ if test $ac_fsusage_space = no; then
 #ifdef HAVE_SYS_MOUNT_H
 #include <sys/mount.h>
 #endif
-#ifdef HAVE_SYS_FS_TYPES_H
-#include <sys/fs_types.h>
-#endif
   int
   main ()
   {
-  struct fs_data fsd;
-  /* Ultrix's statfs returns 1 for success,
-     0 for not mounted, -1 for failure.  */
-  return statfs (".", &fsd) != 1;
+    struct statfs fsd;
+    fsd.f_fsize = 0;
+    return statfs (".", &fsd) != 0;
   }]])],
-    [fu_cv_sys_stat_fs_data=yes],
-    [fu_cv_sys_stat_fs_data=no],
-    [fu_cv_sys_stat_fs_data=no])])
-  AC_MSG_RESULT([$fu_cv_sys_stat_fs_data])
-  if test $fu_cv_sys_stat_fs_data = yes; then
-    ac_fsusage_space=yes
-    AC_DEFINE([STAT_STATFS2_FS_DATA], [1],
-[  Define if statfs takes 2 args and the second argument has
-   type struct fs_data.  (Ultrix)])
+         [fu_cv_sys_stat_statfs2_fsize=yes],
+         [fu_cv_sys_stat_statfs2_fsize=no],
+         [fu_cv_sys_stat_statfs2_fsize=no])
+      ])
+    if test $fu_cv_sys_stat_statfs2_fsize = yes; then
+      ac_fsusage_space=yes
+      AC_DEFINE([STAT_STATFS2_FSIZE], [1],
+        [Define if statfs takes 2 args and struct statfs has a field named f_fsize.
+         (4.4BSD, NetBSD)])
+    fi
   fi
-fi
 
-if test $ac_fsusage_space = no; then
-  # SVR2
-  # (AIX, HP-UX, OSF/1 already handled above.)
-  AC_PREPROC_IFELSE([AC_LANG_SOURCE([[#include <sys/filsys.h>
-        ]])],
-    [AC_DEFINE([STAT_READ_FILSYS], [1],
-      [Define if there is no specific function for reading file systems usage
-       information and you have the <sys/filsys.h> header file.  (SVR2)])
-     ac_fsusage_space=yes])
-fi
-
-AS_IF([test $ac_fsusage_space = yes], [$1], [$2])
+  AS_IF([test $ac_fsusage_space = yes], [$1], [$2])
 
 ])
 
@@ -316,18 +272,22 @@ AS_IF([test $ac_fsusage_space = yes], [$1], [$2])
 # enable the work-around code in fsusage.c.
 AC_DEFUN([gl_STATFS_TRUNCATES],
 [
-  AC_MSG_CHECKING([for statfs that truncates block counts])
-  AC_CACHE_VAL([fu_cv_sys_truncating_statfs],
-  [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+  AC_CACHE_CHECK([for statfs that truncates block counts],
+    [fu_cv_sys_truncating_statfs],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM([[
 #if !defined(sun) && !defined(__sun)
 choke -- this is a workaround for a Sun-specific problem
 #endif
 #include <sys/types.h>
-#include <sys/vfs.h>]],
-      [[struct statfs t; long c = *(t.f_spare);
-        if (c) return 0;]])],
-    [fu_cv_sys_truncating_statfs=yes],
-    [fu_cv_sys_truncating_statfs=no])])
+#include <sys/vfs.h>
+         ]],
+         [[struct statfs t; long c = *(t.f_spare);
+           if (c) return 0;
+         ]])],
+       [fu_cv_sys_truncating_statfs=yes],
+       [fu_cv_sys_truncating_statfs=no])
+    ])
   if test $fu_cv_sys_truncating_statfs = yes; then
     AC_DEFINE([STATFS_TRUNCATES_BLOCK_COUNTS], [1],
       [Define if the block counts reported by statfs may be truncated to 2GB
@@ -335,13 +295,12 @@ choke -- this is a workaround for a Sun-specific problem
        (SunOS 4.1.2, 4.1.3, and 4.1.3_U1 are reported to have this problem.
        SunOS 4.1.1 seems not to be affected.)])
   fi
-  AC_MSG_RESULT([$fu_cv_sys_truncating_statfs])
 ])
 
 
 # Prerequisites of lib/fsusage.c not done by gl_FILE_SYSTEM_USAGE.
 AC_DEFUN([gl_PREREQ_FSUSAGE_EXTRA],
 [
-  AC_CHECK_HEADERS([dustat.h sys/fs/s5param.h sys/filsys.h sys/statfs.h])
+  AC_CHECK_HEADERS([sys/fs/s5param.h sys/statfs.h])
   gl_STATFS_TRUNCATES
 ])
diff --git a/gl/m4/ftell.m4 b/gl/m4/ftell.m4
new file mode 100644
index 00000000..79f1aaf2
--- /dev/null
+++ b/gl/m4/ftell.m4
@@ -0,0 +1,15 @@
+# ftell.m4 serial 3
+dnl Copyright (C) 2007, 2009-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FTELL],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_FTELLO])
+  dnl When ftello needs fixes, ftell needs them too.
+  if test $HAVE_FTELLO = 0 || test $REPLACE_FTELLO = 1; then
+    REPLACE_FTELL=1
+  fi
+])
diff --git a/gl/m4/ftello.m4 b/gl/m4/ftello.m4
new file mode 100644
index 00000000..4901b168
--- /dev/null
+++ b/gl/m4/ftello.m4
@@ -0,0 +1,151 @@
+# ftello.m4 serial 14
+dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FTELLO],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gl_STDIN_LARGE_OFFSET])
+  AC_REQUIRE([gl_SYS_TYPES_H])
+
+  dnl Persuade glibc <stdio.h> to declare ftello().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_DECLS_ONCE([ftello])
+  if test $ac_cv_have_decl_ftello = no; then
+    HAVE_DECL_FTELLO=0
+  fi
+
+  AC_CACHE_CHECK([for ftello], [gl_cv_func_ftello],
+    [
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#include <stdio.h>]],
+           [[ftello (stdin);]])],
+        [gl_cv_func_ftello=yes],
+        [gl_cv_func_ftello=no])
+    ])
+  if test $gl_cv_func_ftello = no; then
+    HAVE_FTELLO=0
+  else
+    if test $WINDOWS_64_BIT_OFF_T = 1; then
+      REPLACE_FTELLO=1
+    fi
+    if test $gl_cv_var_stdin_large_offset = no; then
+      REPLACE_FTELLO=1
+    fi
+    if test $REPLACE_FTELLO = 0; then
+      dnl Detect bug on Solaris.
+      dnl ftell and ftello produce incorrect results after putc that followed a
+      dnl getc call that reached EOF on Solaris. This is because the _IOREAD
+      dnl flag does not get cleared in this case, even though _IOWRT gets set,
+      dnl and ftell and ftello look whether the _IOREAD flag is set.
+      AC_REQUIRE([AC_CANONICAL_HOST])
+      AC_CACHE_CHECK([whether ftello works],
+        [gl_cv_func_ftello_works],
+        [
+          dnl Initial guess, used when cross-compiling or when /dev/tty cannot
+          dnl be opened.
+changequote(,)dnl
+          case "$host_os" in
+                      # Guess no on Solaris.
+            solaris*) gl_cv_func_ftello_works="guessing no" ;;
+                      # Guess yes on native Windows.
+            mingw*)   gl_cv_func_ftello_works="guessing yes" ;;
+                      # Guess yes otherwise.
+            *)        gl_cv_func_ftello_works="guessing yes" ;;
+          esac
+changequote([,])dnl
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#define TESTFILE "conftest.tmp"
+int
+main (void)
+{
+  FILE *fp;
+
+  /* Create a file with some contents.  */
+  fp = fopen (TESTFILE, "w");
+  if (fp == NULL)
+    return 70;
+  if (fwrite ("foogarsh", 1, 8, fp) < 8)
+    { fclose (fp); return 71; }
+  if (fclose (fp))
+    return 72;
+
+  /* The file's contents is now "foogarsh".  */
+
+  /* Try writing after reading to EOF.  */
+  fp = fopen (TESTFILE, "r+");
+  if (fp == NULL)
+    return 73;
+  if (fseek (fp, -1, SEEK_END))
+    { fclose (fp); return 74; }
+  if (!(getc (fp) == 'h'))
+    { fclose (fp); return 1; }
+  if (!(getc (fp) == EOF))
+    { fclose (fp); return 2; }
+  if (!(ftell (fp) == 8))
+    { fclose (fp); return 3; }
+  if (!(ftell (fp) == 8))
+    { fclose (fp); return 4; }
+  if (!(putc ('!', fp) == '!'))
+    { fclose (fp); return 5; }
+  if (!(ftell (fp) == 9))
+    { fclose (fp); return 6; }
+  if (!(fclose (fp) == 0))
+    return 7;
+  fp = fopen (TESTFILE, "r");
+  if (fp == NULL)
+    return 75;
+  {
+    char buf[10];
+    if (!(fread (buf, 1, 10, fp) == 9))
+      { fclose (fp); return 10; }
+    if (!(memcmp (buf, "foogarsh!", 9) == 0))
+      { fclose (fp); return 11; }
+  }
+  if (!(fclose (fp) == 0))
+    return 12;
+
+  /* The file's contents is now "foogarsh!".  */
+
+  return 0;
+}]])],
+            [gl_cv_func_ftello_works=yes],
+            [gl_cv_func_ftello_works=no], [:])
+        ])
+      case "$gl_cv_func_ftello_works" in
+        *yes) ;;
+        *)
+          REPLACE_FTELLO=1
+          AC_DEFINE([FTELLO_BROKEN_AFTER_SWITCHING_FROM_READ_TO_WRITE], [1],
+            [Define to 1 if the system's ftello function has the Solaris bug.])
+          ;;
+      esac
+    fi
+    if test $REPLACE_FTELLO = 0; then
+      dnl Detect bug on macOS >= 10.15.
+      gl_FUNC_UNGETC_WORKS
+      if test $gl_ftello_broken_after_ungetc = yes; then
+        REPLACE_FTELLO=1
+        AC_DEFINE([FTELLO_BROKEN_AFTER_UNGETC], [1],
+          [Define to 1 if the system's ftello function has the macOS bug.])
+      fi
+    fi
+  fi
+])
+
+# Prerequisites of lib/ftello.c.
+AC_DEFUN([gl_PREREQ_FTELLO],
+[
+  dnl Native Windows has the function _ftelli64. mingw hides it, but mingw64
+  dnl makes it usable again.
+  AC_CHECK_FUNCS([_ftelli64])
+])
diff --git a/gl/m4/getaddrinfo.m4 b/gl/m4/getaddrinfo.m4
index 1d631f8c..15f09ffb 100644
--- a/gl/m4/getaddrinfo.m4
+++ b/gl/m4/getaddrinfo.m4
@@ -1,14 +1,13 @@
-# getaddrinfo.m4 serial 30
-dnl Copyright (C) 2004-2013 Free Software Foundation, Inc.
+# getaddrinfo.m4 serial 34
+dnl Copyright (C) 2004-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_GETADDRINFO],
 [
-  AC_REQUIRE([gl_HEADER_SYS_SOCKET])dnl for HAVE_SYS_SOCKET_H, HAVE_WINSOCK2_H
-  AC_REQUIRE([gl_HEADER_NETDB])dnl for HAVE_NETDB_H
-  AC_MSG_NOTICE([checking how to do getaddrinfo, freeaddrinfo and getnameinfo])
+  AC_REQUIRE([gl_SYS_SOCKET_H])dnl for HAVE_SYS_SOCKET_H, HAVE_WINSOCK2_H
+  AC_REQUIRE([gl_NETDB_H])dnl for HAVE_NETDB_H
   GETADDRINFO_LIB=
   gai_saved_LIBS="$LIBS"
 
@@ -55,10 +54,40 @@ AC_DEFUN([gl_GETADDRINFO],
     if test "$gl_cv_w32_getaddrinfo" = "yes"; then
       GETADDRINFO_LIB="-lws2_32"
       LIBS="$gai_saved_LIBS $GETADDRINFO_LIB"
+      dnl Check for correct signature, in particular for a cdecl-compatible
+      dnl calling convention.
+      AC_CACHE_CHECK([for getaddrinfo with POSIX signature],
+        [gl_cv_func_getaddrinfo_posix_signature],
+        [AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETDB_H
+#include <netdb.h>
+#endif
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+#include <stddef.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+int getaddrinfo (const char *, const char *, const struct addrinfo *, struct addrinfo **);
+]])],
+           [gl_cv_func_getaddrinfo_posix_signature=yes],
+           [gl_cv_func_getaddrinfo_posix_signature=no])
+        ])
+      if test $gl_cv_func_getaddrinfo_posix_signature = no; then
+        REPLACE_GETADDRINFO=1
+      fi
     else
       HAVE_GETADDRINFO=0
     fi
   fi
+  AC_DEFINE_UNQUOTED([HAVE_GETADDRINFO], [$HAVE_GETADDRINFO],
+    [Define to 1 if getaddrinfo exists, or to 0 otherwise.])
 
   # We can't use AC_REPLACE_FUNCS here because gai_strerror may be an
   # inline function declared in ws2tcpip.h, so we need to get that
@@ -127,13 +156,13 @@ const char *gai_strerror(int);]])],
 # Prerequisites of lib/netdb.in.h and lib/getaddrinfo.c.
 AC_DEFUN([gl_PREREQ_GETADDRINFO], [
   AC_REQUIRE([gl_NETDB_H_DEFAULTS])
-  AC_REQUIRE([gl_HEADER_SYS_SOCKET])dnl for HAVE_SYS_SOCKET_H, HAVE_WINSOCK2_H
+  AC_REQUIRE([gl_SYS_SOCKET_H])dnl for HAVE_SYS_SOCKET_H, HAVE_WINSOCK2_H
   AC_REQUIRE([gl_HOSTENT]) dnl for HOSTENT_LIB
   AC_REQUIRE([gl_SERVENT]) dnl for SERVENT_LIB
   AC_REQUIRE([gl_FUNC_INET_NTOP]) dnl for INET_NTOP_LIB
   AC_REQUIRE([AC_C_RESTRICT])
   AC_REQUIRE([gl_SOCKET_FAMILIES])
-  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  AC_REQUIRE([gl_SYS_SOCKET_H])
   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   dnl Including sys/socket.h is wrong for Windows, but Windows does not
diff --git a/gl/m4/getdelim.m4 b/gl/m4/getdelim.m4
new file mode 100644
index 00000000..9aaed202
--- /dev/null
+++ b/gl/m4/getdelim.m4
@@ -0,0 +1,111 @@
+# getdelim.m4 serial 16
+
+dnl Copyright (C) 2005-2007, 2009-2023 Free Software Foundation, Inc.
+dnl
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_PREREQ([2.59])
+
+AC_DEFUN([gl_FUNC_GETDELIM],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  dnl Persuade glibc <stdio.h> to declare getdelim().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_DECLS_ONCE([getdelim])
+
+  AC_CHECK_FUNCS_ONCE([getdelim])
+  if test $ac_cv_func_getdelim = yes; then
+    HAVE_GETDELIM=1
+    dnl Found it in some library.  Verify that it works.
+    AC_CACHE_CHECK([for working getdelim function],
+      [gl_cv_func_working_getdelim],
+      [case "$host_os" in
+         darwin*)
+           dnl On macOS 10.13, valgrind detected an out-of-bounds read during
+           dnl the GNU sed test suite:
+           dnl   Invalid read of size 16
+           dnl      at 0x100EE6A05: _platform_memchr$VARIANT$Base (in /usr/lib/system/libsystem_platform.dylib)
+           dnl      by 0x100B7B0BD: getdelim (in /usr/lib/system/libsystem_c.dylib)
+           dnl      by 0x10000B0BE: ck_getdelim (utils.c:254)
+           gl_cv_func_working_getdelim=no ;;
+         *)
+           echo fooNbarN | tr -d '\012' | tr N '\012' > conftest.data
+           AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#    include <stdio.h>
+#    include <stdlib.h>
+#    include <string.h>
+    int main ()
+    {
+      FILE *in = fopen ("./conftest.data", "r");
+      if (!in)
+        return 1;
+      {
+        /* Test result for a NULL buffer and a zero size.
+           Based on a test program from Karl Heuer.  */
+        char *line = NULL;
+        size_t siz = 0;
+        int len = getdelim (&line, &siz, '\n', in);
+        if (!(len == 4 && line && strcmp (line, "foo\n") == 0))
+          { free (line); fclose (in); return 2; }
+        free (line);
+      }
+      {
+        /* Test result for a NULL buffer and a non-zero size.
+           This crashes on FreeBSD 8.0.  */
+        char *line = NULL;
+        size_t siz = (size_t)(~0) / 4;
+        if (getdelim (&line, &siz, '\n', in) == -1)
+          { fclose (in); return 3; }
+        free (line);
+      }
+      fclose (in);
+      return 0;
+    }
+    ]])],
+             [gl_cv_func_working_getdelim=yes],
+             [gl_cv_func_working_getdelim=no],
+             [dnl We're cross compiling.
+              dnl Guess it works on glibc2 systems and musl systems.
+              AC_EGREP_CPP([Lucky GNU user],
+                [
+#include <features.h>
+#ifdef __GNU_LIBRARY__
+ #if (__GLIBC__ >= 2) && !defined __UCLIBC__
+  Lucky GNU user
+ #endif
+#endif
+                ],
+                [gl_cv_func_working_getdelim="guessing yes"],
+                [case "$host_os" in
+                   *-musl*) gl_cv_func_working_getdelim="guessing yes" ;;
+                   *)       gl_cv_func_working_getdelim="$gl_cross_guess_normal" ;;
+                 esac
+                ])
+             ])
+           ;;
+       esac
+      ])
+    case "$gl_cv_func_working_getdelim" in
+      *yes) ;;
+      *) REPLACE_GETDELIM=1 ;;
+    esac
+  else
+    HAVE_GETDELIM=0
+  fi
+
+  if test $ac_cv_have_decl_getdelim = no; then
+    HAVE_DECL_GETDELIM=0
+  fi
+])
+
+# Prerequisites of lib/getdelim.c.
+AC_DEFUN([gl_PREREQ_GETDELIM],
+[
+  AC_CHECK_FUNCS([flockfile funlockfile])
+  AC_CHECK_DECLS([getc_unlocked])
+])
diff --git a/gl/m4/getdtablesize.m4 b/gl/m4/getdtablesize.m4
new file mode 100644
index 00000000..8bcda905
--- /dev/null
+++ b/gl/m4/getdtablesize.m4
@@ -0,0 +1,63 @@
+# getdtablesize.m4 serial 8
+dnl Copyright (C) 2008-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_GETDTABLESIZE],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CHECK_FUNCS_ONCE([getdtablesize])
+  AC_CHECK_DECLS_ONCE([getdtablesize])
+  if test $ac_cv_func_getdtablesize = yes &&
+     test $ac_cv_have_decl_getdtablesize = yes; then
+    AC_CACHE_CHECK([whether getdtablesize works],
+      [gl_cv_func_getdtablesize_works],
+      [dnl There are two concepts: the "maximum possible file descriptor value + 1"
+       dnl and the "maximum number of open file descriptors in a process".
+       dnl Per SUSv2 and POSIX, getdtablesize() should return the first one.
+       dnl On most platforms, the first and the second concept are the same.
+       dnl On OpenVMS, however, they are different and getdtablesize() returns
+       dnl the second one; thus the test below fails. But we don't care
+       dnl because there's no good way to write a replacement getdtablesize().
+       case "$host_os" in
+         vms*) gl_cv_func_getdtablesize_works="no (limitation)" ;;
+         *)
+           dnl Cygwin 1.7.25 automatically increases the RLIMIT_NOFILE soft
+           dnl limit up to an unchangeable hard limit; all other platforms
+           dnl correctly require setrlimit before getdtablesize() can report
+           dnl a larger value.
+           AC_RUN_IFELSE([
+             AC_LANG_PROGRAM(
+               [[#include <unistd.h>]
+                GL_MDA_DEFINES
+               ],
+               [[int size = getdtablesize();
+                 if (dup2 (0, getdtablesize()) != -1)
+                   return 1;
+                 if (size != getdtablesize())
+                   return 2;
+               ]])],
+             [gl_cv_func_getdtablesize_works=yes],
+             [gl_cv_func_getdtablesize_works=no],
+             [case "$host_os" in
+                cygwin*) # on cygwin 1.5.25, getdtablesize() automatically grows
+                  gl_cv_func_getdtablesize_works="guessing no" ;;
+                *) gl_cv_func_getdtablesize_works="guessing yes" ;;
+              esac
+             ])
+           ;;
+       esac
+      ])
+    case "$gl_cv_func_getdtablesize_works" in
+      *yes | "no (limitation)") ;;
+      *) REPLACE_GETDTABLESIZE=1 ;;
+    esac
+  else
+    HAVE_GETDTABLESIZE=0
+  fi
+])
+
+# Prerequisites of lib/getdtablesize.c.
+AC_DEFUN([gl_PREREQ_GETDTABLESIZE], [:])
diff --git a/gl/m4/gethostname.m4 b/gl/m4/gethostname.m4
index 7413f9e3..63f5f636 100644
--- a/gl/m4/gethostname.m4
+++ b/gl/m4/gethostname.m4
@@ -1,5 +1,5 @@
-# gethostname.m4 serial 13
-dnl Copyright (C) 2002, 2008-2013 Free Software Foundation, Inc.
+# gethostname.m4 serial 15
+dnl Copyright (C) 2002, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -48,7 +48,7 @@ AC_DEFUN([gl_PREREQ_HOST_NAME_MAX], [
   dnl - On most Unix systems, use MAXHOSTNAMELEN from <sys/param.h> instead.
   dnl - On Solaris, Cygwin, BeOS, use MAXHOSTNAMELEN from <netdb.h> instead.
   dnl - On mingw, use 256, because
-  dnl   <http://msdn.microsoft.com/en-us/library/ms738527.aspx> says:
+  dnl   <https://docs.microsoft.com/en-us/windows/desktop/api/winsock/nf-winsock-gethostname> says:
   dnl   "if a buffer of 256 bytes is passed in the name parameter and
   dnl    the namelen parameter is set to 256, the buffer size will always
   dnl    be adequate."
@@ -74,7 +74,7 @@ lucky
         dnl mingw.
         gl_cv_decl_HOST_NAME_MAX=256
       else
-        _AC_COMPUTE_INT([MAXHOSTNAMELEN], [gl_cv_decl_HOST_NAME_MAX], [
+        AC_COMPUTE_INT([gl_cv_decl_HOST_NAME_MAX], [MAXHOSTNAMELEN], [
 #include <sys/types.h>
 #if HAVE_SYS_PARAM_H
 # include <sys/param.h>
diff --git a/gl/m4/getline.m4 b/gl/m4/getline.m4
new file mode 100644
index 00000000..03569f06
--- /dev/null
+++ b/gl/m4/getline.m4
@@ -0,0 +1,109 @@
+# getline.m4 serial 30
+
+dnl Copyright (C) 1998-2003, 2005-2007, 2009-2023 Free Software Foundation,
+dnl Inc.
+dnl
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_PREREQ([2.59])
+
+dnl See if there's a working, system-supplied version of the getline function.
+dnl We can't just do AC_REPLACE_FUNCS([getline]) because some systems
+dnl have a function by that name in -linet that doesn't have anything
+dnl to do with the function we need.
+AC_DEFUN([gl_FUNC_GETLINE],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  dnl Persuade glibc <stdio.h> to declare getline().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_DECLS_ONCE([getline])
+
+  gl_getline_needs_run_time_check=no
+  AC_CHECK_FUNC([getline],
+                [dnl Found it in some library.  Verify that it works.
+                 gl_getline_needs_run_time_check=yes],
+                [am_cv_func_working_getline=no])
+  if test $gl_getline_needs_run_time_check = yes; then
+    AC_CACHE_CHECK([for working getline function],
+      [am_cv_func_working_getline],
+      [echo fooNbarN | tr -d '\012' | tr N '\012' > conftest.data
+       AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#    include <stdio.h>
+#    include <stdlib.h>
+#    include <string.h>
+    int main ()
+    {
+      FILE *in = fopen ("./conftest.data", "r");
+      if (!in)
+        return 1;
+      {
+        /* Test result for a NULL buffer and a zero size.
+           Based on a test program from Karl Heuer.  */
+        char *line = NULL;
+        size_t siz = 0;
+        int len = getline (&line, &siz, in);
+        if (!(len == 4 && line && strcmp (line, "foo\n") == 0))
+          { free (line); fclose (in); return 2; }
+        free (line);
+      }
+      {
+        /* Test result for a NULL buffer and a non-zero size.
+           This crashes on FreeBSD 8.0.  */
+        char *line = NULL;
+        size_t siz = (size_t)(~0) / 4;
+        if (getline (&line, &siz, in) == -1)
+          { fclose (in); return 3; }
+        free (line);
+      }
+      fclose (in);
+      return 0;
+    }
+    ]])],
+         [am_cv_func_working_getline=yes],
+         [am_cv_func_working_getline=no],
+         [dnl We're cross compiling.
+          dnl Guess it works on glibc2 systems and musl systems.
+          AC_EGREP_CPP([Lucky GNU user],
+            [
+#include <features.h>
+#ifdef __GNU_LIBRARY__
+ #if (__GLIBC__ >= 2) && !defined __UCLIBC__
+  Lucky GNU user
+ #endif
+#endif
+            ],
+            [am_cv_func_working_getline="guessing yes"],
+            [case "$host_os" in
+               *-musl*) am_cv_func_working_getline="guessing yes" ;;
+               *)       am_cv_func_working_getline="$gl_cross_guess_normal" ;;
+             esac
+            ])
+         ])
+      ])
+  fi
+
+  if test $ac_cv_have_decl_getline = no; then
+    HAVE_DECL_GETLINE=0
+  fi
+
+  case "$am_cv_func_working_getline" in
+    *yes) ;;
+    *)
+      dnl Set REPLACE_GETLINE always: Even if we have not found the broken
+      dnl getline function among $LIBS, it may exist in libinet and the
+      dnl executable may be linked with -linet.
+      REPLACE_GETLINE=1
+      ;;
+  esac
+])
+
+# Prerequisites of lib/getline.c.
+AC_DEFUN([gl_PREREQ_GETLINE],
+[
+  :
+])
diff --git a/gl/m4/getloadavg.m4 b/gl/m4/getloadavg.m4
index 611372aa..79e420ba 100644
--- a/gl/m4/getloadavg.m4
+++ b/gl/m4/getloadavg.m4
@@ -1,13 +1,13 @@
 # Check for getloadavg.
 
-# Copyright (C) 1992-1996, 1999-2000, 2002-2003, 2006, 2008-2013 Free Software
+# Copyright (C) 1992-1996, 1999-2000, 2002-2003, 2006, 2008-2023 Free Software
 # Foundation, Inc.
 
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
-#serial 6
+#serial 10
 
 # Autoconf defines AC_FUNC_GETLOADAVG, but that is obsolescent.
 # New applications should use gl_GETLOADAVG instead.
@@ -22,7 +22,7 @@ AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
 gl_save_LIBS=$LIBS
 
-# getloadvg is present in libc on glibc >= 2.2, Mac OS X, FreeBSD >= 2.0,
+# getloadavg is present in libc on glibc >= 2.2, Mac OS X, FreeBSD >= 2.0,
 # NetBSD >= 0.9, OpenBSD >= 2.0, Solaris >= 7.
 HAVE_GETLOADAVG=1
 AC_CHECK_FUNC([getloadavg], [],
@@ -45,7 +45,9 @@ AC_CHECK_FUNC([getloadavg], [],
      # There is a commonly available library for RS/6000 AIX.
      # Since it is not a standard part of AIX, it might be installed locally.
      gl_getloadavg_LIBS=$LIBS
-     LIBS="-L/usr/local/lib $LIBS"
+     if test $cross_compiling != yes; then
+       LIBS="-L/usr/local/lib $LIBS"
+     fi
      AC_CHECK_LIB([getloadavg], [getloadavg],
                   [LIBS="-lgetloadavg $LIBS" gl_func_getloadavg_done=yes],
                   [LIBS=$gl_getloadavg_LIBS])
@@ -92,6 +94,9 @@ else
 fi
 AC_CHECK_DECL([getloadavg], [], [HAVE_DECL_GETLOADAVG=0],
   [[#if HAVE_SYS_LOADAVG_H
+    /* OpenIndiana has a bug: <sys/time.h> must be included before
+       <sys/loadavg.h>.  */
+    # include <sys/time.h>
     # include <sys/loadavg.h>
     #endif
     #include <stdlib.h>]])
@@ -105,7 +110,7 @@ AC_DEFUN([gl_PREREQ_GETLOADAVG],
 [
 # Figure out what our getloadavg.c needs.
 
-AC_CHECK_HEADERS_ONCE([sys/param.h])
+AC_CHECK_HEADERS_ONCE([sys/param.h unistd.h])
 
 # On HPUX9, an unprivileged user can get load averages this way.
 if test $gl_func_getloadavg_done = no; then
@@ -142,7 +147,7 @@ fi
 AC_CHECK_HEADERS([nlist.h],
 [AC_CHECK_MEMBERS([struct nlist.n_un.n_name],
                   [], [],
-                  [@%:@include <nlist.h>])
+                  [#include <nlist.h>])
  AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <nlist.h>]],
                    [[struct nlist x;
                     #ifdef HAVE_STRUCT_NLIST_N_UN_N_NAME
diff --git a/gl/m4/getopt.m4 b/gl/m4/getopt.m4
index 50f45091..7981a095 100644
--- a/gl/m4/getopt.m4
+++ b/gl/m4/getopt.m4
@@ -1,5 +1,5 @@
-# getopt.m4 serial 44
-dnl Copyright (C) 2002-2006, 2008-2013 Free Software Foundation, Inc.
+# getopt.m4 serial 48
+dnl Copyright (C) 2002-2006, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -21,6 +21,8 @@ AC_DEFUN([gl_FUNC_GETOPT_POSIX],
       REPLACE_GETOPT=1
     fi
   ])
+  GL_GENERATE_GETOPT_H=false
+  GL_GENERATE_GETOPT_CDEFS_H=false
   if test $REPLACE_GETOPT = 1; then
     dnl Arrange for getopt.h to be created.
     gl_GETOPT_SUBSTITUTE_HEADER
@@ -32,9 +34,16 @@ AC_DEFUN([gl_FUNC_GETOPT_POSIX],
 # getopt_long_only.
 AC_DEFUN([gl_FUNC_GETOPT_GNU],
 [
+  dnl Set the variable gl_getopt_required, so that all invocations of
+  dnl gl_GETOPT_CHECK_HEADERS in the scope of the current configure file
+  dnl will check for getopt with GNU extensions.
+  dnl This means that if one gnulib-tool invocation requests getopt-posix
+  dnl and another gnulib-tool invocation requests getopt-gnu, it is as if
+  dnl both had requested getopt-gnu.
   m4_divert_text([INIT_PREPARE], [gl_getopt_required=GNU])
 
-  AC_REQUIRE([gl_FUNC_GETOPT_POSIX])
+  dnl No need to invoke gl_FUNC_GETOPT_POSIX here; this is automatically
+  dnl done through the module dependency getopt-gnu -> getopt-posix.
 ])
 
 # Determine whether to replace the entire getopt facility.
@@ -295,8 +304,10 @@ dnl is ambiguous with environment values that contain newlines.
            ]])],
         [gl_cv_func_getopt_gnu=yes],
         [gl_cv_func_getopt_gnu=no],
-        [dnl Cross compiling. Assume the worst, even on glibc platforms.
-         gl_cv_func_getopt_gnu="guessing no"
+        [dnl Cross compiling.
+         dnl Assume the worst, even on glibc platforms.
+         dnl But obey --enable-cross-guesses.
+         gl_cv_func_getopt_gnu="$gl_cross_guess_normal"
         ])
        case $gl_had_POSIXLY_CORRECT in
          exported) ;;
@@ -354,15 +365,17 @@ dnl is ambiguous with environment values that contain newlines.
 
 AC_DEFUN([gl_GETOPT_SUBSTITUTE_HEADER],
 [
-  GETOPT_H=getopt.h
+  AC_CHECK_HEADERS_ONCE([sys/cdefs.h])
+  if test $ac_cv_header_sys_cdefs_h = yes; then
+    HAVE_SYS_CDEFS_H=1
+  else
+    HAVE_SYS_CDEFS_H=0
+  fi
+  AC_SUBST([HAVE_SYS_CDEFS_H])
+
   AC_DEFINE([__GETOPT_PREFIX], [[rpl_]],
     [Define to rpl_ if the getopt replacement functions and variables
      should be used.])
-  AC_SUBST([GETOPT_H])
-])
-
-# Prerequisites of lib/getopt*.
-AC_DEFUN([gl_PREREQ_GETOPT],
-[
-  AC_CHECK_DECLS_ONCE([getenv])
+  GL_GENERATE_GETOPT_H=true
+  GL_GENERATE_GETOPT_CDEFS_H=true
 ])
diff --git a/gl/m4/getprogname.m4 b/gl/m4/getprogname.m4
new file mode 100644
index 00000000..b67c527c
--- /dev/null
+++ b/gl/m4/getprogname.m4
@@ -0,0 +1,43 @@
+# getprogname.m4 - check for getprogname or replacements for it
+
+# Copyright (C) 2016-2023 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# serial 4
+
+AC_DEFUN([gl_FUNC_GETPROGNAME],
+[
+  AC_CHECK_FUNCS_ONCE([getprogname getexecname])
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  ac_found=0
+  AC_CHECK_DECLS([program_invocation_name], [ac_found=1], [],
+    [#include <errno.h>])
+  AC_CHECK_DECLS([program_invocation_short_name], [ac_found=1], [],
+    [#include <errno.h>])
+  AC_CHECK_DECLS([__argv], [ac_found=1], [], [#include <stdlib.h>])
+
+  # Incur the cost of this test only if none of the above worked.
+  if test $ac_found = 0; then
+    # On OpenBSD 5.1, using the global __progname variable appears to be
+    # the only way to implement getprogname.
+    AC_CACHE_CHECK([whether __progname is defined in default libraries],
+      [gl_cv_var___progname],
+      [
+        gl_cv_var___progname=
+        AC_LINK_IFELSE(
+          [AC_LANG_PROGRAM(
+            [[extern char *__progname;]],
+            [[return *__progname;]]
+          )],
+          [gl_cv_var___progname=yes]
+        )
+      ]
+    )
+    if test "$gl_cv_var___progname" = yes; then
+      AC_DEFINE([HAVE_VAR___PROGNAME], 1,
+        [Define if you have a global __progname variable])
+    fi
+  fi
+])
diff --git a/gl/m4/gettext.m4 b/gl/m4/gettext.m4
index 8d1f0665..a0eda3d8 100644
--- a/gl/m4/gettext.m4
+++ b/gl/m4/gettext.m4
@@ -1,16 +1,16 @@
-# gettext.m4 serial 66 (gettext-0.18.2)
-dnl Copyright (C) 1995-2013 Free Software Foundation, Inc.
+# gettext.m4 serial 71 (gettext-0.20.2)
+dnl Copyright (C) 1995-2014, 2016, 2018-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 dnl
-dnl This file can can be used in projects which are not available under
-dnl the GNU General Public License or the GNU Library General Public
+dnl This file can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Lesser General Public
 dnl License but which still want to provide support for the GNU gettext
 dnl functionality.
 dnl Please note that the actual code of the GNU gettext library is covered
-dnl by the GNU Library General Public License, and the rest of the GNU
-dnl gettext package package is covered by the GNU General Public License.
+dnl by the GNU Lesser General Public License, and the rest of the GNU
+dnl gettext package is covered by the GNU General Public License.
 dnl They are *not* in the public domain.
 
 dnl Authors:
@@ -20,15 +20,13 @@ dnl   Bruno Haible <haible@clisp.cons.org>, 2000-2006, 2008-2010.
 dnl Macro to add for using GNU gettext.
 
 dnl Usage: AM_GNU_GETTEXT([INTLSYMBOL], [NEEDSYMBOL], [INTLDIR]).
-dnl INTLSYMBOL can be one of 'external', 'no-libtool', 'use-libtool'. The
-dnl    default (if it is not specified or empty) is 'no-libtool'.
-dnl    INTLSYMBOL should be 'external' for packages with no intl directory,
-dnl    and 'no-libtool' or 'use-libtool' for packages with an intl directory.
+dnl INTLSYMBOL must be one of 'external', 'use-libtool'.
+dnl    INTLSYMBOL should be 'external' for packages other than GNU gettext, and
+dnl    'use-libtool' for the packages 'gettext-runtime' and 'gettext-tools'.
 dnl    If INTLSYMBOL is 'use-libtool', then a libtool library
 dnl    $(top_builddir)/intl/libintl.la will be created (shared and/or static,
 dnl    depending on --{enable,disable}-{shared,static} and on the presence of
-dnl    AM-DISABLE-SHARED). If INTLSYMBOL is 'no-libtool', a static library
-dnl    $(top_builddir)/intl/libintl.a will be created.
+dnl    AM-DISABLE-SHARED).
 dnl If NEEDSYMBOL is specified and is 'need-ngettext', then GNU gettext
 dnl    implementations (in libc or libintl) without the ngettext() function
 dnl    will be ignored.  If NEEDSYMBOL is specified and is
@@ -57,19 +55,17 @@ dnl
 AC_DEFUN([AM_GNU_GETTEXT],
 [
   dnl Argument checking.
-  ifelse([$1], [], , [ifelse([$1], [external], , [ifelse([$1], [no-libtool], , [ifelse([$1], [use-libtool], ,
+  ifelse([$1], [], , [ifelse([$1], [external], , [ifelse([$1], [use-libtool], ,
     [errprint([ERROR: invalid first argument to AM_GNU_GETTEXT
-])])])])])
+])])])])
   ifelse(ifelse([$1], [], [old])[]ifelse([$1], [no-libtool], [old]), [old],
-    [AC_DIAGNOSE([obsolete], [Use of AM_GNU_GETTEXT without [external] argument is deprecated.])])
+    [errprint([ERROR: Use of AM_GNU_GETTEXT without [external] argument is no longer supported.
+])])
   ifelse([$2], [], , [ifelse([$2], [need-ngettext], , [ifelse([$2], [need-formatstring-macros], ,
     [errprint([ERROR: invalid second argument to AM_GNU_GETTEXT
 ])])])])
   define([gt_included_intl],
-    ifelse([$1], [external],
-      ifdef([AM_GNU_GETTEXT_][INTL_SUBDIR], [yes], [no]),
-      [yes]))
-  define([gt_libtool_suffix_prefix], ifelse([$1], [use-libtool], [l], []))
+    ifelse([$1], [external], [no], [yes]))
   gt_NEEDS_INIT
   AM_GNU_GETTEXT_NEED([$2])
 
@@ -91,8 +87,7 @@ AC_DEFUN([AM_GNU_GETTEXT],
   dnl again, outside any 'if'. There are two solutions:
   dnl - Invoke AM_ICONV_LINKFLAGS_BODY here, outside any 'if'.
   dnl - Control the expansions in more detail using AC_PROVIDE_IFELSE.
-  dnl Since AC_PROVIDE_IFELSE is only in autoconf >= 2.52 and not
-  dnl documented, we avoid it.
+  dnl Since AC_PROVIDE_IFELSE is not documented, we avoid it.
   ifelse(gt_included_intl, yes, , [
     AC_REQUIRE([AM_ICONV_LINKFLAGS_BODY])
   ])
@@ -161,13 +156,18 @@ changequote([,])dnl
             [AC_LANG_PROGRAM(
                [[
 #include <libintl.h>
-$gt_revision_test_code
+#ifndef __GNU_GETTEXT_SUPPORTED_REVISION
 extern int _nl_msg_cat_cntr;
 extern int *_nl_domain_bindings;
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION (_nl_msg_cat_cntr + *_nl_domain_bindings)
+#else
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION 0
+#endif
+$gt_revision_test_code
                ]],
                [[
 bindtextdomain ("", "");
-return * gettext ("")$gt_expression_test_code + _nl_msg_cat_cntr + *_nl_domain_bindings
+return * gettext ("")$gt_expression_test_code + __GNU_GETTEXT_SYMBOL_EXPRESSION
                ]])],
             [eval "$gt_func_gnugettext_libc=yes"],
             [eval "$gt_func_gnugettext_libc=no"])])
@@ -193,17 +193,22 @@ return * gettext ("")$gt_expression_test_code + _nl_msg_cat_cntr + *_nl_domain_b
               [AC_LANG_PROGRAM(
                  [[
 #include <libintl.h>
-$gt_revision_test_code
+#ifndef __GNU_GETTEXT_SUPPORTED_REVISION
 extern int _nl_msg_cat_cntr;
 extern
 #ifdef __cplusplus
 "C"
 #endif
 const char *_nl_expand_alias (const char *);
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION (_nl_msg_cat_cntr + *_nl_expand_alias (""))
+#else
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION 0
+#endif
+$gt_revision_test_code
                  ]],
                  [[
 bindtextdomain ("", "");
-return * gettext ("")$gt_expression_test_code + _nl_msg_cat_cntr + *_nl_expand_alias ("")
+return * gettext ("")$gt_expression_test_code + __GNU_GETTEXT_SYMBOL_EXPRESSION
                  ]])],
               [eval "$gt_func_gnugettext_libintl=yes"],
               [eval "$gt_func_gnugettext_libintl=no"])
@@ -214,17 +219,22 @@ return * gettext ("")$gt_expression_test_code + _nl_msg_cat_cntr + *_nl_expand_a
                 [AC_LANG_PROGRAM(
                    [[
 #include <libintl.h>
-$gt_revision_test_code
+#ifndef __GNU_GETTEXT_SUPPORTED_REVISION
 extern int _nl_msg_cat_cntr;
 extern
 #ifdef __cplusplus
 "C"
 #endif
 const char *_nl_expand_alias (const char *);
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION (_nl_msg_cat_cntr + *_nl_expand_alias (""))
+#else
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION 0
+#endif
+$gt_revision_test_code
                    ]],
                    [[
 bindtextdomain ("", "");
-return * gettext ("")$gt_expression_test_code + _nl_msg_cat_cntr + *_nl_expand_alias ("")
+return * gettext ("")$gt_expression_test_code + __GNU_GETTEXT_SYMBOL_EXPRESSION
                    ]])],
                 [LIBINTL="$LIBINTL $LIBICONV"
                  LTLIBINTL="$LTLIBINTL $LTLIBICONV"
@@ -263,8 +273,8 @@ return * gettext ("")$gt_expression_test_code + _nl_msg_cat_cntr + *_nl_expand_a
         dnl Mark actions used to generate GNU NLS library.
         BUILD_INCLUDED_LIBINTL=yes
         USE_INCLUDED_LIBINTL=yes
-        LIBINTL="ifelse([$3],[],\${top_builddir}/intl,[$3])/libintl.[]gt_libtool_suffix_prefix[]a $LIBICONV $LIBTHREAD"
-        LTLIBINTL="ifelse([$3],[],\${top_builddir}/intl,[$3])/libintl.[]gt_libtool_suffix_prefix[]a $LTLIBICONV $LTLIBTHREAD"
+        LIBINTL="ifelse([$3],[],\${top_builddir}/intl,[$3])/libintl.la $LIBICONV $LIBTHREAD"
+        LTLIBINTL="ifelse([$3],[],\${top_builddir}/intl,[$3])/libintl.la $LTLIBICONV $LTLIBTHREAD"
         LIBS=`echo " $LIBS " | sed -e 's/ -lintl / /' -e 's/^ //' -e 's/ $//'`
       fi
 
@@ -332,43 +342,14 @@ return * gettext ("")$gt_expression_test_code + _nl_msg_cat_cntr + *_nl_expand_a
   fi
 
   ifelse(gt_included_intl, yes, [
-    dnl If this is used in GNU gettext we have to set BUILD_INCLUDED_LIBINTL
-    dnl to 'yes' because some of the testsuite requires it.
-    if test "$PACKAGE" = gettext-runtime || test "$PACKAGE" = gettext-tools; then
-      BUILD_INCLUDED_LIBINTL=yes
-    fi
+    dnl In GNU gettext we have to set BUILD_INCLUDED_LIBINTL to 'yes'
+    dnl because some of the testsuite requires it.
+    BUILD_INCLUDED_LIBINTL=yes
 
     dnl Make all variables we use known to autoconf.
     AC_SUBST([BUILD_INCLUDED_LIBINTL])
     AC_SUBST([USE_INCLUDED_LIBINTL])
     AC_SUBST([CATOBJEXT])
-
-    dnl For backward compatibility. Some configure.ins may be using this.
-    nls_cv_header_intl=
-    nls_cv_header_libgt=
-
-    dnl For backward compatibility. Some Makefiles may be using this.
-    DATADIRNAME=share
-    AC_SUBST([DATADIRNAME])
-
-    dnl For backward compatibility. Some Makefiles may be using this.
-    INSTOBJEXT=.mo
-    AC_SUBST([INSTOBJEXT])
-
-    dnl For backward compatibility. Some Makefiles may be using this.
-    GENCAT=gencat
-    AC_SUBST([GENCAT])
-
-    dnl For backward compatibility. Some Makefiles may be using this.
-    INTLOBJS=
-    if test "$USE_INCLUDED_LIBINTL" = yes; then
-      INTLOBJS="\$(GETTOBJS)"
-    fi
-    AC_SUBST([INTLOBJS])
-
-    dnl Enable libtool support if the surrounding package wishes it.
-    INTL_LIBTOOL_SUFFIX_PREFIX=gt_libtool_suffix_prefix
-    AC_SUBST([INTL_LIBTOOL_SUFFIX_PREFIX])
   ])
 
   dnl For backward compatibility. Some Makefiles may be using this.
@@ -399,3 +380,7 @@ AC_DEFUN([AM_GNU_GETTEXT_NEED],
 
 dnl Usage: AM_GNU_GETTEXT_VERSION([gettext-version])
 AC_DEFUN([AM_GNU_GETTEXT_VERSION], [])
+
+
+dnl Usage: AM_GNU_GETTEXT_REQUIRE_VERSION([gettext-version])
+AC_DEFUN([AM_GNU_GETTEXT_REQUIRE_VERSION], [])
diff --git a/gl/m4/gl-openssl.m4 b/gl/m4/gl-openssl.m4
new file mode 100644
index 00000000..7eab4e10
--- /dev/null
+++ b/gl/m4/gl-openssl.m4
@@ -0,0 +1,76 @@
+# gl-openssl.m4 serial 6
+dnl Copyright (C) 2013-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_SET_CRYPTO_CHECK_DEFAULT],
+[
+  m4_define([gl_CRYPTO_CHECK_DEFAULT], [$1])
+])
+gl_SET_CRYPTO_CHECK_DEFAULT([no])
+
+AC_DEFUN([gl_CRYPTO_CHECK],
+[
+  dnl gnulib users set this before gl_INIT with gl_SET_CRYPTO_CHECK_DEFAULT()
+  m4_divert_once([DEFAULTS], [with_openssl_default='gl_CRYPTO_CHECK_DEFAULT'])
+
+  dnl Only clear once, so crypto routines can be checked for individually
+  m4_divert_once([DEFAULTS], [LIB_CRYPTO=])
+
+  AC_ARG_WITH([openssl],
+    [[  --with-openssl[=ARG]    use libcrypto hash routines for the hash functions
+                          MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512.
+                          Valid ARGs are:
+                            'yes',
+                            'no',
+                            'auto' => use if any version available,
+                            'auto-gpl-compat' => use if GPL compatible version
+                                                 available,
+                            'optional' => use if available
+                                          and warn if not available;
+                          Default is ']gl_CRYPTO_CHECK_DEFAULT['.]m4_ifdef([gl_AF_ALG], [
+                          Note also --with-linux-crypto, which will enable the
+                          use of Linux kernel crypto routines (if available),
+                          which has precedence for files.])],
+    [],
+    [with_openssl=$with_openssl_default])
+
+  AC_SUBST([LIB_CRYPTO])
+  if test "x$with_openssl" != xno; then
+    if test "x$with_openssl" = xauto-gpl-compat; then
+      AC_CACHE_CHECK([whether openssl is GPL compatible],
+                     [gl_cv_openssl_gpl_compat],
+        [AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM([[
+                #include <openssl/opensslv.h>
+                #if OPENSSL_VERSION_MAJOR < 3
+                  #error "openssl >= version 3 not found"
+                #endif
+              ]])],
+           [gl_cv_openssl_gpl_compat=yes],
+           [gl_cv_openssl_gpl_compat=no])])
+    fi
+    if test "x$with_openssl" != xauto-gpl-compat ||
+       test "x$gl_cv_openssl_gpl_compat" = xyes; then
+      AC_CHECK_LIB([crypto], [$1],
+        [AC_CHECK_HEADERS(
+           m4_if([$1], [MD5], [openssl/md5.h], [openssl/sha.h]),
+           [LIB_CRYPTO=-lcrypto
+            AC_DEFINE([HAVE_OPENSSL_$1], [1],
+              [Define to 1 if libcrypto is used for $1.])])])
+    fi
+    if test "x$LIB_CRYPTO" = x; then
+      message='openssl development library not found for $1.
+  If you want to install it, first find the pre-built package name:
+    - On Debian and Debian-based systems: libssl-dev,
+    - On Red Hat distributions: openssl-devel.
+    - Other: https://repology.org/project/openssl/versions'
+      if test "x$with_openssl" = xyes; then
+        AC_MSG_ERROR([$message])
+      elif test "x$with_openssl" = xoptional; then
+        AC_MSG_WARN([$message])
+      fi
+    fi
+  fi
+])
diff --git a/gl/m4/glibc2.m4 b/gl/m4/glibc2.m4
deleted file mode 100644
index 0e506826..00000000
--- a/gl/m4/glibc2.m4
+++ /dev/null
@@ -1,31 +0,0 @@
-# glibc2.m4 serial 3
-dnl Copyright (C) 2000-2002, 2004, 2008, 2010-2013 Free Software Foundation,
-dnl Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-# Test for the GNU C Library, version 2.0 or newer.
-# From Bruno Haible.
-
-AC_DEFUN([gt_GLIBC2],
-  [
-    AC_CACHE_CHECK([whether we are using the GNU C Library 2 or newer],
-      [ac_cv_gnu_library_2],
-      [AC_EGREP_CPP([Lucky GNU user],
-        [
-#include <features.h>
-#ifdef __GNU_LIBRARY__
- #if (__GLIBC__ >= 2) && !defined __UCLIBC__
-  Lucky GNU user
- #endif
-#endif
-        ],
-        [ac_cv_gnu_library_2=yes],
-        [ac_cv_gnu_library_2=no])
-      ]
-    )
-    AC_SUBST([GLIBC2])
-    GLIBC2="$ac_cv_gnu_library_2"
-  ]
-)
diff --git a/gl/m4/glibc21.m4 b/gl/m4/glibc21.m4
deleted file mode 100644
index 613fb2a4..00000000
--- a/gl/m4/glibc21.m4
+++ /dev/null
@@ -1,34 +0,0 @@
-# glibc21.m4 serial 5
-dnl Copyright (C) 2000-2002, 2004, 2008, 2010-2013 Free Software Foundation,
-dnl Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-# Test for the GNU C Library, version 2.1 or newer, or uClibc.
-# From Bruno Haible.
-
-AC_DEFUN([gl_GLIBC21],
-  [
-    AC_CACHE_CHECK([whether we are using the GNU C Library >= 2.1 or uClibc],
-      [ac_cv_gnu_library_2_1],
-      [AC_EGREP_CPP([Lucky],
-        [
-#include <features.h>
-#ifdef __GNU_LIBRARY__
- #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1) || (__GLIBC__ > 2)
-  Lucky GNU user
- #endif
-#endif
-#ifdef __UCLIBC__
- Lucky user
-#endif
-        ],
-        [ac_cv_gnu_library_2_1=yes],
-        [ac_cv_gnu_library_2_1=no])
-      ]
-    )
-    AC_SUBST([GLIBC21])
-    GLIBC21="$ac_cv_gnu_library_2_1"
-  ]
-)
diff --git a/gl/m4/gnulib-cache.m4 b/gl/m4/gnulib-cache.m4
index 90ad4aaa..ee4756e5 100644
--- a/gl/m4/gnulib-cache.m4
+++ b/gl/m4/gnulib-cache.m4
@@ -1,8 +1,8 @@
-# Copyright (C) 2002-2013 Free Software Foundation, Inc.
+# Copyright (C) 2002-2023 Free Software Foundation, Inc.
 #
 # This file is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 3 of the License, or
+# the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This file is distributed in the hope that it will be useful,
@@ -11,7 +11,7 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
-# along with this file.  If not, see <http://www.gnu.org/licenses/>.
+# along with this file.  If not, see <https://www.gnu.org/licenses/>.
 #
 # As a special exception to the GNU General Public License,
 # this file may be distributed as part of a program that
@@ -27,7 +27,39 @@
 
 
 # Specification in the form of a command-line invocation:
-#   gnulib-tool --import --dir=. --lib=libgnu --source-base=gl --m4-base=gl/m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --no-conditional-dependencies --no-libtool --macro-prefix=gl --no-vc-files base64 crypto/sha1 dirname environ floorf fsusage getaddrinfo gethostname getloadavg getopt-gnu gettext idpriv-droptemp mountlist regex setenv strcase strcasestr strsep timegm unsetenv vasprintf vsnprintf
+# gnulib-tool --import \
+#  --lib=libgnu \
+#  --source-base=gl \
+#  --m4-base=gl/m4 \
+#  --doc-base=doc \
+#  --tests-base=tests \
+#  --aux-dir=build-aux \
+#  --no-conditional-dependencies \
+#  --no-libtool \
+#  --macro-prefix=gl \
+#  --no-vc-files \
+#  base64 \
+#  crypto/sha1 \
+#  dirname \
+#  environ \
+#  floorf \
+#  fsusage \
+#  getaddrinfo \
+#  gethostname \
+#  getloadavg \
+#  getopt-gnu \
+#  gettext \
+#  idpriv-droptemp \
+#  mountlist \
+#  regex \
+#  setenv \
+#  strcase \
+#  strcasestr \
+#  strsep \
+#  timegm \
+#  unsetenv \
+#  vasprintf \
+#  vsnprintf
 
 # Specification in the form of a few gnulib-tool.m4 macro invocations:
 gl_LOCAL_DIR([])
diff --git a/gl/m4/gnulib-common.m4 b/gl/m4/gnulib-common.m4
index 0ae5a9ec..facc3404 100644
--- a/gl/m4/gnulib-common.m4
+++ b/gl/m4/gnulib-common.m4
@@ -1,25 +1,59 @@
-# gnulib-common.m4 serial 33
-dnl Copyright (C) 2007-2013 Free Software Foundation, Inc.
+# gnulib-common.m4 serial 75a
+dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
+AC_PREREQ([2.62])
+
 # gl_COMMON
 # is expanded unconditionally through gnulib-tool magic.
 AC_DEFUN([gl_COMMON], [
   dnl Use AC_REQUIRE here, so that the code is expanded once only.
   AC_REQUIRE([gl_00GNULIB])
   AC_REQUIRE([gl_COMMON_BODY])
+  AC_REQUIRE([gl_ZZGNULIB])
 ])
 AC_DEFUN([gl_COMMON_BODY], [
+  AH_VERBATIM([_GL_GNUC_PREREQ],
+[/* True if the compiler says it groks GNU C version MAJOR.MINOR.  */
+#if defined __GNUC__ && defined __GNUC_MINOR__
+# define _GL_GNUC_PREREQ(major, minor) \
+    ((major) < __GNUC__ + ((minor) <= __GNUC_MINOR__))
+#else
+# define _GL_GNUC_PREREQ(major, minor) 0
+#endif
+])
   AH_VERBATIM([_Noreturn],
 [/* The _Noreturn keyword of C11.  */
-#if ! (defined _Noreturn \
-       || (defined __STDC_VERSION__ && 201112 <= __STDC_VERSION__))
-# if (3 <= __GNUC__ || (__GNUC__ == 2 && 8 <= __GNUC_MINOR__) \
-      || 0x5110 <= __SUNPRO_C)
+#ifndef _Noreturn
+# if (defined __cplusplus \
+      && ((201103 <= __cplusplus && !(__GNUC__ == 4 && __GNUC_MINOR__ == 7)) \
+          || (defined _MSC_VER && 1900 <= _MSC_VER)) \
+      && 0)
+    /* [[noreturn]] is not practically usable, because with it the syntax
+         extern _Noreturn void func (...);
+       would not be valid; such a declaration would only be valid with 'extern'
+       and '_Noreturn' swapped, or without the 'extern' keyword.  However, some
+       AIX system header files and several gnulib header files use precisely
+       this syntax with 'extern'.  */
+#  define _Noreturn [[noreturn]]
+# elif (defined __clang__ && __clang_major__ < 16 \
+        && defined _GL_WORK_AROUND_LLVM_BUG_59792)
+   /* Compile with -D_GL_WORK_AROUND_LLVM_BUG_59792 to work around
+      that rare LLVM bug, though you may get many false-alarm warnings.  */
+#  define _Noreturn
+# elif ((!defined __cplusplus || defined __clang__) \
+        && (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) \
+            || (!defined __STRICT_ANSI__ \
+                && (_GL_GNUC_PREREQ (4, 7) \
+                    || (defined __apple_build_version__ \
+                        ? 6000000 <= __apple_build_version__ \
+                        : 3 < __clang_major__ + (5 <= __clang_minor__))))))
+   /* _Noreturn works as-is.  */
+# elif _GL_GNUC_PREREQ (2, 8) || defined __clang__ || 0x5110 <= __SUNPRO_C
 #  define _Noreturn __attribute__ ((__noreturn__))
-# elif defined _MSC_VER && 1200 <= _MSC_VER
+# elif 1200 <= (defined _MSC_VER ? _MSC_VER : 0)
 #  define _Noreturn __declspec (noreturn)
 # else
 #  define _Noreturn
@@ -36,33 +70,519 @@ AC_DEFUN([gl_COMMON_BODY], [
 #if defined __APPLE__ && defined __MACH__ && __APPLE_CC__ >= 5465 && !defined __cplusplus && __STDC_VERSION__ >= 199901L && !defined __GNUC_STDC_INLINE__
 # define __GNUC_STDC_INLINE__ 1
 #endif])
-  AH_VERBATIM([unused_parameter],
-[/* Define as a marker that can be attached to declarations that might not
-    be used.  This helps to reduce warnings, such as from
-    GCC -Wunused-parameter.  */
-#if __GNUC__ >= 3 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
-# define _GL_UNUSED __attribute__ ((__unused__))
+  AH_VERBATIM([attribute],
+[/* Attributes.  */
+#if (defined __has_attribute \
+     && (!defined __clang_minor__ \
+         || (defined __apple_build_version__ \
+             ? 6000000 <= __apple_build_version__ \
+             : 3 < __clang_major__ + (5 <= __clang_minor__))))
+# define _GL_HAS_ATTRIBUTE(attr) __has_attribute (__##attr##__)
 #else
-# define _GL_UNUSED
+# define _GL_HAS_ATTRIBUTE(attr) _GL_ATTR_##attr
+# define _GL_ATTR_alloc_size _GL_GNUC_PREREQ (4, 3)
+# define _GL_ATTR_always_inline _GL_GNUC_PREREQ (3, 2)
+# define _GL_ATTR_artificial _GL_GNUC_PREREQ (4, 3)
+# define _GL_ATTR_cold _GL_GNUC_PREREQ (4, 3)
+# define _GL_ATTR_const _GL_GNUC_PREREQ (2, 95)
+# define _GL_ATTR_deprecated _GL_GNUC_PREREQ (3, 1)
+# define _GL_ATTR_diagnose_if 0
+# define _GL_ATTR_error _GL_GNUC_PREREQ (4, 3)
+# define _GL_ATTR_externally_visible _GL_GNUC_PREREQ (4, 1)
+# define _GL_ATTR_fallthrough _GL_GNUC_PREREQ (7, 0)
+# define _GL_ATTR_format _GL_GNUC_PREREQ (2, 7)
+# define _GL_ATTR_leaf _GL_GNUC_PREREQ (4, 6)
+# define _GL_ATTR_malloc _GL_GNUC_PREREQ (3, 0)
+# ifdef _ICC
+#  define _GL_ATTR_may_alias 0
+# else
+#  define _GL_ATTR_may_alias _GL_GNUC_PREREQ (3, 3)
+# endif
+# define _GL_ATTR_noinline _GL_GNUC_PREREQ (3, 1)
+# define _GL_ATTR_nonnull _GL_GNUC_PREREQ (3, 3)
+# define _GL_ATTR_nonstring _GL_GNUC_PREREQ (8, 0)
+# define _GL_ATTR_nothrow _GL_GNUC_PREREQ (3, 3)
+# define _GL_ATTR_packed _GL_GNUC_PREREQ (2, 7)
+# define _GL_ATTR_pure _GL_GNUC_PREREQ (2, 96)
+# define _GL_ATTR_returns_nonnull _GL_GNUC_PREREQ (4, 9)
+# define _GL_ATTR_sentinel _GL_GNUC_PREREQ (4, 0)
+# define _GL_ATTR_unused _GL_GNUC_PREREQ (2, 7)
+# define _GL_ATTR_warn_unused_result _GL_GNUC_PREREQ (3, 4)
 #endif
-/* The name _UNUSED_PARAMETER_ is an earlier spelling, although the name
-   is a misnomer outside of parameter lists.  */
-#define _UNUSED_PARAMETER_ _GL_UNUSED
 
-/* The __pure__ attribute was added in gcc 2.96.  */
-#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 96)
-# define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
-#else
-# define _GL_ATTRIBUTE_PURE /* empty */
+/* Disable GCC -Wpedantic if using __has_c_attribute and this is not C23+.  */
+#if (defined __has_c_attribute && _GL_GNUC_PREREQ (4, 6) \
+     && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) <= 201710)
+# pragma GCC diagnostic ignored "-Wpedantic"
 #endif
 
-/* The __const__ attribute was added in gcc 2.95.  */
-#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 95)
-# define _GL_ATTRIBUTE_CONST __attribute__ ((__const__))
-#else
-# define _GL_ATTRIBUTE_CONST /* empty */
+]dnl There is no _GL_ATTRIBUTE_ALIGNED; use stdalign's alignas instead.
+[
+/* _GL_ATTRIBUTE_ALLOC_SIZE ((N)) declares that the Nth argument of the function
+   is the size of the returned memory block.
+   _GL_ATTRIBUTE_ALLOC_SIZE ((M, N)) declares that the Mth argument multiplied
+   by the Nth argument of the function is the size of the returned memory block.
+ */
+/* Applies to: function, pointer to function, function types.  */
+#ifndef _GL_ATTRIBUTE_ALLOC_SIZE
+# if _GL_HAS_ATTRIBUTE (alloc_size)
+#  define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args))
+# else
+#  define _GL_ATTRIBUTE_ALLOC_SIZE(args)
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_ALWAYS_INLINE tells that the compiler should always inline the
+   function and report an error if it cannot do so.  */
+/* Applies to: function.  */
+#ifndef _GL_ATTRIBUTE_ALWAYS_INLINE
+# if _GL_HAS_ATTRIBUTE (always_inline)
+#  define _GL_ATTRIBUTE_ALWAYS_INLINE __attribute__ ((__always_inline__))
+# else
+#  define _GL_ATTRIBUTE_ALWAYS_INLINE
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_ARTIFICIAL declares that the function is not important to show
+    in stack traces when debugging.  The compiler should omit the function from
+    stack traces.  */
+/* Applies to: function.  */
+#ifndef _GL_ATTRIBUTE_ARTIFICIAL
+# if _GL_HAS_ATTRIBUTE (artificial)
+#  define _GL_ATTRIBUTE_ARTIFICIAL __attribute__ ((__artificial__))
+# else
+#  define _GL_ATTRIBUTE_ARTIFICIAL
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_COLD declares that the function is rarely executed.  */
+/* Applies to: functions.  */
+/* Avoid __attribute__ ((cold)) on MinGW; see thread starting at
+   <https://lists.gnu.org/r/emacs-devel/2019-04/msg01152.html>.
+   Also, Oracle Studio 12.6 requires 'cold' not '__cold__'.  */
+#ifndef _GL_ATTRIBUTE_COLD
+# if _GL_HAS_ATTRIBUTE (cold) && !defined __MINGW32__
+#  ifndef __SUNPRO_C
+#   define _GL_ATTRIBUTE_COLD __attribute__ ((__cold__))
+#  else
+#   define _GL_ATTRIBUTE_COLD __attribute__ ((cold))
+#  endif
+# else
+#  define _GL_ATTRIBUTE_COLD
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_CONST declares that it is OK for a compiler to omit duplicate
+   calls to the function with the same arguments.
+   This attribute is safe for a function that neither depends on nor affects
+   observable state, and always returns exactly once - e.g., does not loop
+   forever, and does not call longjmp.
+   (This attribute is stricter than _GL_ATTRIBUTE_PURE.)  */
+/* Applies to: functions.  */
+#ifndef _GL_ATTRIBUTE_CONST
+# if _GL_HAS_ATTRIBUTE (const)
+#  define _GL_ATTRIBUTE_CONST __attribute__ ((__const__))
+# else
+#  define _GL_ATTRIBUTE_CONST
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_DEALLOC (F, I) declares that the function returns pointers
+   that can be freed by passing them as the Ith argument to the
+   function F.
+   _GL_ATTRIBUTE_DEALLOC_FREE declares that the function returns pointers that
+   can be freed via 'free'; it can be used only after declaring 'free'.  */
+/* Applies to: functions.  Cannot be used on inline functions.  */
+#ifndef _GL_ATTRIBUTE_DEALLOC
+# if _GL_GNUC_PREREQ (11, 0)
+#  define _GL_ATTRIBUTE_DEALLOC(f, i) __attribute__ ((__malloc__ (f, i)))
+# else
+#  define _GL_ATTRIBUTE_DEALLOC(f, i)
+# endif
+#endif
+/* If gnulib's <string.h> or <wchar.h> has already defined this macro, continue
+   to use this earlier definition, since <stdlib.h> may not have been included
+   yet.  */
+#ifndef _GL_ATTRIBUTE_DEALLOC_FREE
+# if defined __cplusplus && defined __GNUC__ && !defined __clang__
+/* Work around GCC bug <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108231> */
+#  define _GL_ATTRIBUTE_DEALLOC_FREE \
+     _GL_ATTRIBUTE_DEALLOC ((void (*) (void *)) free, 1)
+# else
+#  define _GL_ATTRIBUTE_DEALLOC_FREE \
+     _GL_ATTRIBUTE_DEALLOC (free, 1)
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_DEPRECATED: Declares that an entity is deprecated.
+   The compiler may warn if the entity is used.  */
+/* Applies to:
+     - function, variable,
+     - struct, union, struct/union member,
+     - enumeration, enumeration item,
+     - typedef,
+   in C++ also: namespace, class, template specialization.  */
+#ifndef _GL_ATTRIBUTE_DEPRECATED
+# ifdef __has_c_attribute
+#  if __has_c_attribute (__deprecated__)
+#   define _GL_ATTRIBUTE_DEPRECATED [[__deprecated__]]
+#  endif
+# endif
+# if !defined _GL_ATTRIBUTE_DEPRECATED && _GL_HAS_ATTRIBUTE (deprecated)
+#  define _GL_ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__))
+# endif
+# ifndef _GL_ATTRIBUTE_DEPRECATED
+#  define _GL_ATTRIBUTE_DEPRECATED
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_ERROR(msg) requests an error if a function is called and
+   the function call is not optimized away.
+   _GL_ATTRIBUTE_WARNING(msg) requests a warning if a function is called and
+   the function call is not optimized away.  */
+/* Applies to: functions.  */
+#if !(defined _GL_ATTRIBUTE_ERROR && defined _GL_ATTRIBUTE_WARNING)
+# if _GL_HAS_ATTRIBUTE (error)
+#  define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__error__ (msg)))
+#  define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__warning__ (msg)))
+# elif _GL_HAS_ATTRIBUTE (diagnose_if)
+#  define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__diagnose_if__ (1, msg, "error")))
+#  define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__diagnose_if__ (1, msg, "warning")))
+# else
+#  define _GL_ATTRIBUTE_ERROR(msg)
+#  define _GL_ATTRIBUTE_WARNING(msg)
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_EXTERNALLY_VISIBLE declares that the entity should remain
+   visible to debuggers etc., even with '-fwhole-program'.  */
+/* Applies to: functions, variables.  */
+#ifndef _GL_ATTRIBUTE_EXTERNALLY_VISIBLE
+# if _GL_HAS_ATTRIBUTE (externally_visible)
+#  define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE __attribute__ ((externally_visible))
+# else
+#  define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_FALLTHROUGH declares that it is not a programming mistake if
+   the control flow falls through to the immediately following 'case' or
+   'default' label.  The compiler should not warn in this case.  */
+/* Applies to: Empty statement (;), inside a 'switch' statement.  */
+/* Always expands to something.  */
+#ifndef _GL_ATTRIBUTE_FALLTHROUGH
+# ifdef __has_c_attribute
+#  if __has_c_attribute (__fallthrough__)
+#   define _GL_ATTRIBUTE_FALLTHROUGH [[__fallthrough__]]
+#  endif
+# endif
+# if !defined _GL_ATTRIBUTE_FALLTHROUGH && _GL_HAS_ATTRIBUTE (fallthrough)
+#  define _GL_ATTRIBUTE_FALLTHROUGH __attribute__ ((__fallthrough__))
+# endif
+# ifndef _GL_ATTRIBUTE_FALLTHROUGH
+#  define _GL_ATTRIBUTE_FALLTHROUGH ((void) 0)
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_FORMAT ((ARCHETYPE, STRING-INDEX, FIRST-TO-CHECK))
+   declares that the STRING-INDEXth function argument is a format string of
+   style ARCHETYPE, which is one of:
+     printf, gnu_printf
+     scanf, gnu_scanf,
+     strftime, gnu_strftime,
+     strfmon,
+   or the same thing prefixed and suffixed with '__'.
+   If FIRST-TO-CHECK is not 0, arguments starting at FIRST-TO_CHECK
+   are suitable for the format string.  */
+/* Applies to: functions.  */
+#ifndef _GL_ATTRIBUTE_FORMAT
+# if _GL_HAS_ATTRIBUTE (format)
+#  define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+# else
+#  define _GL_ATTRIBUTE_FORMAT(spec)
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_LEAF declares that if the function is called from some other
+   compilation unit, it executes code from that unit only by return or by
+   exception handling.  This declaration lets the compiler optimize that unit
+   more aggressively.  */
+/* Applies to: functions.  */
+#ifndef _GL_ATTRIBUTE_LEAF
+# if _GL_HAS_ATTRIBUTE (leaf)
+#  define _GL_ATTRIBUTE_LEAF __attribute__ ((__leaf__))
+# else
+#  define _GL_ATTRIBUTE_LEAF
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_MALLOC declares that the function returns a pointer to freshly
+   allocated memory.  */
+/* Applies to: functions.  */
+#ifndef _GL_ATTRIBUTE_MALLOC
+# if _GL_HAS_ATTRIBUTE (malloc)
+#  define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
+# else
+#  define _GL_ATTRIBUTE_MALLOC
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_MAY_ALIAS declares that pointers to the type may point to the
+   same storage as pointers to other types.  Thus this declaration disables
+   strict aliasing optimization.  */
+/* Applies to: types.  */
+/* Oracle Studio 12.6 mishandles may_alias despite __has_attribute OK.  */
+#ifndef _GL_ATTRIBUTE_MAY_ALIAS
+# if _GL_HAS_ATTRIBUTE (may_alias) && !defined __SUNPRO_C
+#  define _GL_ATTRIBUTE_MAY_ALIAS __attribute__ ((__may_alias__))
+# else
+#  define _GL_ATTRIBUTE_MAY_ALIAS
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_MAYBE_UNUSED declares that it is not a programming mistake if
+   the entity is not used.  The compiler should not warn if the entity is not
+   used.  */
+/* Applies to:
+     - function, variable,
+     - struct, union, struct/union member,
+     - enumeration, enumeration item,
+     - typedef,
+   in C++ also: class.  */
+/* In C++ and C23, this is spelled [[__maybe_unused__]].
+   GCC's syntax is __attribute__ ((__unused__)).
+   clang supports both syntaxes.  */
+#ifndef _GL_ATTRIBUTE_MAYBE_UNUSED
+# ifdef __has_c_attribute
+#  if __has_c_attribute (__maybe_unused__)
+#   define _GL_ATTRIBUTE_MAYBE_UNUSED [[__maybe_unused__]]
+#  endif
+# endif
+# ifndef _GL_ATTRIBUTE_MAYBE_UNUSED
+#  define _GL_ATTRIBUTE_MAYBE_UNUSED _GL_ATTRIBUTE_UNUSED
+# endif
+#endif
+/* Alternative spelling of this macro, for convenience and for
+   compatibility with glibc/include/libc-symbols.h.  */
+#define _GL_UNUSED _GL_ATTRIBUTE_MAYBE_UNUSED
+/* Earlier spellings of this macro.  */
+#define _UNUSED_PARAMETER_ _GL_ATTRIBUTE_MAYBE_UNUSED
+
+/* _GL_ATTRIBUTE_NODISCARD declares that the caller of the function should not
+   discard the return value.  The compiler may warn if the caller does not use
+   the return value, unless the caller uses something like ignore_value.  */
+/* Applies to: function, enumeration, class.  */
+#ifndef _GL_ATTRIBUTE_NODISCARD
+# ifdef __has_c_attribute
+#  if __has_c_attribute (__nodiscard__)
+#   define _GL_ATTRIBUTE_NODISCARD [[__nodiscard__]]
+#  endif
+# endif
+# if !defined _GL_ATTRIBUTE_NODISCARD && _GL_HAS_ATTRIBUTE (warn_unused_result)
+#  define _GL_ATTRIBUTE_NODISCARD __attribute__ ((__warn_unused_result__))
+# endif
+# ifndef _GL_ATTRIBUTE_NODISCARD
+#  define _GL_ATTRIBUTE_NODISCARD
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_NOINLINE tells that the compiler should not inline the
+   function.  */
+/* Applies to: functions.  */
+#ifndef _GL_ATTRIBUTE_NOINLINE
+# if _GL_HAS_ATTRIBUTE (noinline)
+#  define _GL_ATTRIBUTE_NOINLINE __attribute__ ((__noinline__))
+# else
+#  define _GL_ATTRIBUTE_NOINLINE
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_NONNULL ((N1, N2,...)) declares that the arguments N1, N2,...
+   must not be NULL.
+   _GL_ATTRIBUTE_NONNULL () declares that all pointer arguments must not be
+   null.  */
+/* Applies to: functions.  */
+#ifndef _GL_ATTRIBUTE_NONNULL
+# if _GL_HAS_ATTRIBUTE (nonnull)
+#  define _GL_ATTRIBUTE_NONNULL(args) __attribute__ ((__nonnull__ args))
+# else
+#  define _GL_ATTRIBUTE_NONNULL(args)
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_NONSTRING declares that the contents of a character array is
+   not meant to be NUL-terminated.  */
+/* Applies to: struct/union members and variables that are arrays of element
+   type '[[un]signed] char'.  */
+#ifndef _GL_ATTRIBUTE_NONSTRING
+# if _GL_HAS_ATTRIBUTE (nonstring)
+#  define _GL_ATTRIBUTE_NONSTRING __attribute__ ((__nonstring__))
+# else
+#  define _GL_ATTRIBUTE_NONSTRING
+# endif
+#endif
+
+/* There is no _GL_ATTRIBUTE_NORETURN; use _Noreturn instead.  */
+
+/* _GL_ATTRIBUTE_NOTHROW declares that the function does not throw exceptions.
+ */
+/* Applies to: functions.  */
+#ifndef _GL_ATTRIBUTE_NOTHROW
+# if _GL_HAS_ATTRIBUTE (nothrow) && !defined __cplusplus
+#  define _GL_ATTRIBUTE_NOTHROW __attribute__ ((__nothrow__))
+# else
+#  define _GL_ATTRIBUTE_NOTHROW
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_PACKED declares:
+   For struct members: The member has the smallest possible alignment.
+   For struct, union, class: All members have the smallest possible alignment,
+   minimizing the memory required.  */
+/* Applies to: struct members, struct, union,
+   in C++ also: class.  */
+#ifndef _GL_ATTRIBUTE_PACKED
+# if _GL_HAS_ATTRIBUTE (packed)
+#  define _GL_ATTRIBUTE_PACKED __attribute__ ((__packed__))
+# else
+#  define _GL_ATTRIBUTE_PACKED
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_PURE declares that It is OK for a compiler to omit duplicate
+   calls to the function with the same arguments if observable state is not
+   changed between calls.
+   This attribute is safe for a function that does not affect
+   observable state, and always returns exactly once.
+   (This attribute is looser than _GL_ATTRIBUTE_CONST.)  */
+/* Applies to: functions.  */
+#ifndef _GL_ATTRIBUTE_PURE
+# if _GL_HAS_ATTRIBUTE (pure)
+#  define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
+# else
+#  define _GL_ATTRIBUTE_PURE
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_RETURNS_NONNULL declares that the function's return value is
+   a non-NULL pointer.  */
+/* Applies to: functions.  */
+#ifndef _GL_ATTRIBUTE_RETURNS_NONNULL
+# if _GL_HAS_ATTRIBUTE (returns_nonnull)
+#  define _GL_ATTRIBUTE_RETURNS_NONNULL __attribute__ ((__returns_nonnull__))
+# else
+#  define _GL_ATTRIBUTE_RETURNS_NONNULL
+# endif
+#endif
+
+/* _GL_ATTRIBUTE_SENTINEL(pos) declares that the variadic function expects a
+   trailing NULL argument.
+   _GL_ATTRIBUTE_SENTINEL () - The last argument is NULL (requires C99).
+   _GL_ATTRIBUTE_SENTINEL ((N)) - The (N+1)st argument from the end is NULL.  */
+/* Applies to: functions.  */
+#ifndef _GL_ATTRIBUTE_SENTINEL
+# if _GL_HAS_ATTRIBUTE (sentinel)
+#  define _GL_ATTRIBUTE_SENTINEL(pos) __attribute__ ((__sentinel__ pos))
+# else
+#  define _GL_ATTRIBUTE_SENTINEL(pos)
+# endif
+#endif
+
+/* A helper macro.  Don't use it directly.  */
+#ifndef _GL_ATTRIBUTE_UNUSED
+# if _GL_HAS_ATTRIBUTE (unused)
+#  define _GL_ATTRIBUTE_UNUSED __attribute__ ((__unused__))
+# else
+#  define _GL_ATTRIBUTE_UNUSED
+# endif
+#endif
+
+]dnl There is no _GL_ATTRIBUTE_VISIBILITY; see m4/visibility.m4 instead.
+[
+/* _GL_UNUSED_LABEL; declares that it is not a programming mistake if the
+   immediately preceding label is not used.  The compiler should not warn
+   if the label is not used.  */
+/* Applies to: label (both in C and C++).  */
+/* Note that g++ < 4.5 does not support the '__attribute__ ((__unused__)) ;'
+   syntax.  But clang does.  */
+#ifndef _GL_UNUSED_LABEL
+# if !(defined __cplusplus && !_GL_GNUC_PREREQ (4, 5)) || defined __clang__
+#  define _GL_UNUSED_LABEL _GL_ATTRIBUTE_UNUSED
+# else
+#  define _GL_UNUSED_LABEL
+# endif
 #endif
 ])
+  AH_VERBATIM([async_safe],
+[/* The _GL_ASYNC_SAFE marker should be attached to functions that are
+   signal handlers (for signals other than SIGABRT, SIGPIPE) or can be
+   invoked from such signal handlers.  Such functions have some restrictions:
+     * All functions that it calls should be marked _GL_ASYNC_SAFE as well,
+       or should be listed as async-signal-safe in POSIX
+       <https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04>
+       section 2.4.3.  Note that malloc(), sprintf(), and fwrite(), in
+       particular, are NOT async-signal-safe.
+     * All memory locations (variables and struct fields) that these functions
+       access must be marked 'volatile'.  This holds for both read and write
+       accesses.  Otherwise the compiler might optimize away stores to and
+       reads from such locations that occur in the program, depending on its
+       data flow analysis.  For example, when the program contains a loop
+       that is intended to inspect a variable set from within a signal handler
+           while (!signal_occurred)
+             ;
+       the compiler is allowed to transform this into an endless loop if the
+       variable 'signal_occurred' is not declared 'volatile'.
+   Additionally, recall that:
+     * A signal handler should not modify errno (except if it is a handler
+       for a fatal signal and ends by raising the same signal again, thus
+       provoking the termination of the process).  If it invokes a function
+       that may clobber errno, it needs to save and restore the value of
+       errno.  */
+#define _GL_ASYNC_SAFE
+])
+  AH_VERBATIM([micro_optimizations],
+[/* _GL_CMP (n1, n2) performs a three-valued comparison on n1 vs. n2, where
+   n1 and n2 are expressions without side effects, that evaluate to real
+   numbers (excluding NaN).
+   It returns
+     1  if n1 > n2
+     0  if n1 == n2
+     -1 if n1 < n2
+   The naïve code   (n1 > n2 ? 1 : n1 < n2 ? -1 : 0)  produces a conditional
+   jump with nearly all GCC versions up to GCC 10.
+   This variant     (n1 < n2 ? -1 : n1 > n2)  produces a conditional with many
+   GCC versions up to GCC 9.
+   The better code  (n1 > n2) - (n1 < n2)  from Hacker's Delight § 2-9
+   avoids conditional jumps in all GCC versions >= 3.4.  */
+#define _GL_CMP(n1, n2) (((n1) > (n2)) - ((n1) < (n2)))
+])
+  dnl Hint which direction to take regarding cross-compilation guesses:
+  dnl When a user installs a program on a platform they are not intimately
+  dnl familiar with, --enable-cross-guesses=conservative is the appropriate
+  dnl choice.  It implements the "If we don't know, assume the worst" principle.
+  dnl However, when an operating system developer (on a platform which is not
+  dnl yet known to gnulib) builds packages for their platform, they want to
+  dnl expose, not hide, possible platform bugs; in this case,
+  dnl --enable-cross-guesses=risky is the appropriate choice.
+  dnl Sets the variables
+  dnl gl_cross_guess_normal    (to be used when 'yes' is good and 'no' is bad),
+  dnl gl_cross_guess_inverted  (to be used when 'no' is good and 'yes' is bad).
+  AC_ARG_ENABLE([cross-guesses],
+    [AS_HELP_STRING([--enable-cross-guesses={conservative|risky}],
+       [specify policy for cross-compilation guesses])],
+    [if test "x$enableval" != xconservative && test "x$enableval" != xrisky; then
+       AC_MSG_WARN([invalid argument supplied to --enable-cross-guesses])
+       enableval=conservative
+     fi
+     gl_cross_guesses="$enableval"],
+    [gl_cross_guesses=conservative])
+  if test $gl_cross_guesses = risky; then
+    gl_cross_guess_normal="guessing yes"
+    gl_cross_guess_inverted="guessing no"
+  else
+    gl_cross_guess_normal="guessing no"
+    gl_cross_guess_inverted="guessing yes"
+  fi
   dnl Preparation for running test programs:
   dnl Tell glibc to write diagnostics from -D_FORTIFY_SOURCE=2 to stderr, not
   dnl to /dev/tty, so they can be redirected to log files.  Such diagnostics
@@ -71,6 +591,16 @@ AC_DEFUN([gl_COMMON_BODY], [
   export LIBC_FATAL_STDERR_
 ])
 
+# gl_MODULE_INDICATOR_INIT_VARIABLE([variablename])
+# gl_MODULE_INDICATOR_INIT_VARIABLE([variablename], [initialvalue])
+# initializes the shell variable that indicates the presence of the given module
+# as a C preprocessor expression.
+AC_DEFUN([gl_MODULE_INDICATOR_INIT_VARIABLE],
+[
+  GL_MODULE_INDICATOR_PREFIX[]_[$1]=m4_if([$2], , [0], [$2])
+  AC_SUBST(GL_MODULE_INDICATOR_PREFIX[]_[$1])
+])
+
 # gl_MODULE_INDICATOR_CONDITION
 # expands to a C preprocessor expression that evaluates to 1 or 0, depending
 # whether a gnulib module that has been requested shall be considered present
@@ -83,9 +613,9 @@ m4_define([gl_MODULE_INDICATOR_CONDITION], [1])
 AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE],
 [
   gl_MODULE_INDICATOR_SET_VARIABLE_AUX(
-    [GNULIB_[]m4_translit([[$1]],
-                          [abcdefghijklmnopqrstuvwxyz./-],
-                          [ABCDEFGHIJKLMNOPQRSTUVWXYZ___])],
+    [GL_MODULE_INDICATOR_PREFIX[]_GNULIB_[]m4_translit([[$1]],
+                                                       [abcdefghijklmnopqrstuvwxyz./-],
+                                                       [ABCDEFGHIJKLMNOPQRSTUVWXYZ___])],
     [gl_MODULE_INDICATOR_CONDITION])
 ])
 
@@ -197,42 +727,20 @@ AC_DEFUN([gl_FEATURES_H],
   AC_SUBST([HAVE_FEATURES_H])
 ])
 
-# m4_foreach_w
-# is a backport of autoconf-2.59c's m4_foreach_w.
-# Remove this macro when we can assume autoconf >= 2.60.
-m4_ifndef([m4_foreach_w],
-  [m4_define([m4_foreach_w],
-    [m4_foreach([$1], m4_split(m4_normalize([$2]), [ ]), [$3])])])
-
-# AS_VAR_IF(VAR, VALUE, [IF-MATCH], [IF-NOT-MATCH])
-# ----------------------------------------------------
-# Backport of autoconf-2.63b's macro.
-# Remove this macro when we can assume autoconf >= 2.64.
-m4_ifndef([AS_VAR_IF],
-[m4_define([AS_VAR_IF],
-[AS_IF([test x"AS_VAR_GET([$1])" = x""$2], [$3], [$4])])])
-
 # gl_PROG_CC_C99
 # Modifies the value of the shell variable CC in an attempt to make $CC
 # understand ISO C99 source code.
-# This is like AC_PROG_CC_C99, except that
-# - AC_PROG_CC_C99 did not exist in Autoconf versions < 2.60,
-# - AC_PROG_CC_C99 does not mix well with AC_PROG_CC_STDC
-#   <http://lists.gnu.org/archive/html/bug-gnulib/2011-09/msg00367.html>,
-#   but many more packages use AC_PROG_CC_STDC than AC_PROG_CC_C99
-#   <http://lists.gnu.org/archive/html/bug-gnulib/2011-09/msg00441.html>.
-# Remaining problems:
-# - When AC_PROG_CC_STDC is invoked twice, it adds the C99 enabling options
-#   to CC twice
-#   <http://lists.gnu.org/archive/html/bug-gnulib/2011-09/msg00431.html>.
-# - AC_PROG_CC_STDC is likely to change now that C11 is an ISO standard.
 AC_DEFUN([gl_PROG_CC_C99],
 [
-  dnl Change that version number to the minimum Autoconf version that supports
-  dnl mixing AC_PROG_CC_C99 calls with AC_PROG_CC_STDC calls.
-  m4_version_prereq([9.0],
-    [AC_REQUIRE([AC_PROG_CC_C99])],
-    [AC_REQUIRE([AC_PROG_CC_STDC])])
+  dnl Just use AC_PROG_CC_C99.
+  dnl When AC_PROG_CC_C99 and AC_PROG_CC_STDC are used together, the substituted
+  dnl value of CC will contain the C99 enabling options twice. But this is only
+  dnl a cosmetic problem.
+  dnl With Autoconf >= 2.70, use AC_PROG_CC since it implies AC_PROG_CC_C99;
+  dnl this avoids a "warning: The macro `AC_PROG_CC_C99' is obsolete."
+  m4_version_prereq([2.70],
+    [AC_REQUIRE([AC_PROG_CC])],
+    [AC_REQUIRE([AC_PROG_CC_C99])])
 ])
 
 # gl_PROG_AR_RANLIB
@@ -243,9 +751,11 @@ AC_DEFUN([gl_PROG_AR_RANLIB],
 [
   dnl Minix 3 comes with two toolchains: The Amsterdam Compiler Kit compiler
   dnl as "cc", and GCC as "gcc". They have different object file formats and
-  dnl library formats. In particular, the GNU binutils programs ar, ranlib
+  dnl library formats. In particular, the GNU binutils programs ar and ranlib
   dnl produce libraries that work only with gcc, not with cc.
   AC_REQUIRE([AC_PROG_CC])
+  dnl The '][' hides this use from 'aclocal'.
+  AC_BEFORE([$0], [A][M_PROG_AR])
   AC_CACHE_CHECK([for Minix Amsterdam compiler], [gl_cv_c_amsterdam_compiler],
     [
       AC_EGREP_CPP([Amsterdam],
@@ -257,25 +767,39 @@ Amsterdam
         [gl_cv_c_amsterdam_compiler=yes],
         [gl_cv_c_amsterdam_compiler=no])
     ])
-  if test -z "$AR"; then
-    if test $gl_cv_c_amsterdam_compiler = yes; then
+
+  dnl Don't compete with AM_PROG_AR's decision about AR/ARFLAGS if we are not
+  dnl building with __ACK__.
+  if test $gl_cv_c_amsterdam_compiler = yes; then
+    if test -z "$AR"; then
       AR='cc -c.a'
-      if test -z "$ARFLAGS"; then
-        ARFLAGS='-o'
-      fi
-    else
-      dnl Use the Automake-documented default values for AR and ARFLAGS,
-      dnl but prefer ${host}-ar over ar (useful for cross-compiling).
-      AC_CHECK_TOOL([AR], [ar], [ar])
-      if test -z "$ARFLAGS"; then
-        ARFLAGS='cru'
-      fi
     fi
-  else
     if test -z "$ARFLAGS"; then
-      ARFLAGS='cru'
+      ARFLAGS='-o'
     fi
+  else
+    dnl AM_PROG_AR was added in automake v1.11.2.  AM_PROG_AR does not AC_SUBST
+    dnl ARFLAGS variable (it is filed into Makefile.in directly by automake
+    dnl script on-demand, if not specified by ./configure of course).
+    dnl Don't AC_REQUIRE the AM_PROG_AR otherwise the code for __ACK__ above
+    dnl will be ignored.  Also, pay attention to call AM_PROG_AR in else block
+    dnl because AM_PROG_AR is written so it could re-set AR variable even for
+    dnl __ACK__.  It may seem like its easier to avoid calling the macro here,
+    dnl but we need to AC_SUBST both AR/ARFLAGS (thus those must have some good
+    dnl default value and automake should usually know them).
+    dnl
+    dnl The '][' hides this use from 'aclocal'.
+    m4_ifdef([A][M_PROG_AR], [A][M_PROG_AR], [:])
   fi
+
+  dnl In case the code above has not helped with setting AR/ARFLAGS, use
+  dnl Automake-documented default values for AR and ARFLAGS, but prefer
+  dnl ${host}-ar over ar (useful for cross-compiling).
+  AC_CHECK_TOOL([AR], [ar], [ar])
+  if test -z "$ARFLAGS"; then
+    ARFLAGS='cr'
+  fi
+
   AC_SUBST([AR])
   AC_SUBST([ARFLAGS])
   if test -z "$RANLIB"; then
@@ -289,46 +813,29 @@ Amsterdam
   AC_SUBST([RANLIB])
 ])
 
-# AC_PROG_MKDIR_P
-# is a backport of autoconf-2.60's AC_PROG_MKDIR_P, with a fix
-# for interoperability with automake-1.9.6 from autoconf-2.62.
-# Remove this macro when we can assume autoconf >= 2.62 or
-# autoconf >= 2.60 && automake >= 1.10.
-# AC_AUTOCONF_VERSION was introduced in 2.62, so use that as the witness.
-m4_ifndef([AC_AUTOCONF_VERSION],[
-m4_ifdef([AC_PROG_MKDIR_P], [
-  dnl For automake-1.9.6 && autoconf < 2.62: Ensure MKDIR_P is AC_SUBSTed.
-  m4_define([AC_PROG_MKDIR_P],
-    m4_defn([AC_PROG_MKDIR_P])[
-    AC_SUBST([MKDIR_P])])], [
-  dnl For autoconf < 2.60: Backport of AC_PROG_MKDIR_P.
-  AC_DEFUN_ONCE([AC_PROG_MKDIR_P],
-    [AC_REQUIRE([AM_PROG_MKDIR_P])dnl defined by automake
-     MKDIR_P='$(mkdir_p)'
-     AC_SUBST([MKDIR_P])])])
-])
-
 # AC_C_RESTRICT
-# This definition overrides the AC_C_RESTRICT macro from autoconf 2.60..2.61,
-# so that mixed use of GNU C and GNU C++ and mixed use of Sun C and Sun C++
-# works.
-# This definition can be removed once autoconf >= 2.62 can be assumed.
-# AC_AUTOCONF_VERSION was introduced in 2.62, so use that as the witness.
-m4_ifndef([AC_AUTOCONF_VERSION],[
+# This definition is copied from post-2.70 Autoconf and overrides the
+# AC_C_RESTRICT macro from autoconf 2.60..2.70.
+m4_version_prereq([2.70.1], [], [
 AC_DEFUN([AC_C_RESTRICT],
 [AC_CACHE_CHECK([for C/C++ restrict keyword], [ac_cv_c_restrict],
   [ac_cv_c_restrict=no
-   # The order here caters to the fact that C++ does not require restrict.
-   for ac_kw in __restrict __restrict__ _Restrict restrict; do
-     AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
-      [[typedef int * int_ptr;
-        int foo (int_ptr $ac_kw ip) {
-        return ip[0];
-       }]],
-      [[int s[1];
-        int * $ac_kw t = s;
-        t[0] = 0;
-        return foo(t)]])],
+   # Put '__restrict__' first, to avoid problems with glibc and non-GCC; see:
+   # https://lists.gnu.org/archive/html/bug-autoconf/2016-02/msg00006.html
+   # Put 'restrict' last, because C++ lacks it.
+   for ac_kw in __restrict__ __restrict _Restrict restrict; do
+     AC_COMPILE_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[typedef int *int_ptr;
+           int foo (int_ptr $ac_kw ip) { return ip[0]; }
+           int bar (int [$ac_kw]); /* Catch GCC bug 14050.  */
+           int bar (int ip[$ac_kw]) { return ip[0]; }
+         ]],
+         [[int s[1];
+           int *$ac_kw t = s;
+           t[0] = 0;
+           return foo (t) + bar (t);
+         ]])],
       [ac_cv_c_restrict=$ac_kw])
      test "$ac_cv_c_restrict" != no && break
    done
@@ -336,22 +843,24 @@ AC_DEFUN([AC_C_RESTRICT],
  AH_VERBATIM([restrict],
 [/* Define to the equivalent of the C99 'restrict' keyword, or to
    nothing if this is not supported.  Do not define if restrict is
-   supported directly.  */
+   supported only directly.  */
 #undef restrict
-/* Work around a bug in Sun C++: it does not support _Restrict, even
-   though the corresponding Sun C compiler does, which causes
-   "#define restrict _Restrict" in the previous line.  Perhaps some future
-   version of Sun C++ will work with _Restrict; if so, it'll probably
-   define __RESTRICT, just as Sun C does.  */
-#if defined __SUNPRO_CC && !defined __RESTRICT
+/* Work around a bug in older versions of Sun C++, which did not
+   #define __restrict__ or support _Restrict or __restrict__
+   even though the corresponding Sun C compiler ended up with
+   "#define restrict _Restrict" or "#define restrict __restrict__"
+   in the previous line.  This workaround can be removed once
+   we assume Oracle Developer Studio 12.5 (2016) or later.  */
+#if defined __SUNPRO_CC && !defined __RESTRICT && !defined __restrict__
 # define _Restrict
+# define __restrict__
 #endif])
  case $ac_cv_c_restrict in
    restrict) ;;
    no) AC_DEFINE([restrict], []) ;;
    *)  AC_DEFINE_UNQUOTED([restrict], [$ac_cv_c_restrict]) ;;
  esac
-])
+])# AC_C_RESTRICT
 ])
 
 # gl_BIGENDIAN
@@ -363,6 +872,22 @@ AC_DEFUN([gl_BIGENDIAN],
   AC_C_BIGENDIAN
 ])
 
+# A temporary file descriptor.
+# Must be less than 10, because dash 0.5.8 does not support redirections
+# with multi-digit file descriptors.
+m4_define([GL_TMP_FD], 9)
+
+# gl_SILENT(command)
+# executes command, but without the normal configure output.
+# This is useful when you want to invoke AC_CACHE_CHECK (or AC_CHECK_FUNC etc.)
+# inside another AC_CACHE_CHECK.
+AC_DEFUN([gl_SILENT],
+[
+  exec GL_TMP_FD>&AS_MESSAGE_FD AS_MESSAGE_FD>/dev/null
+  $1
+  exec AS_MESSAGE_FD>&GL_TMP_FD GL_TMP_FD>&-
+])
+
 # gl_CACHE_VAL_SILENT(cache-id, command-to-set-it)
 # is like AC_CACHE_VAL(cache-id, command-to-set-it), except that it does not
 # output a spurious "(cached)" mark in the midst of other configure output.
@@ -370,8 +895,257 @@ AC_DEFUN([gl_BIGENDIAN],
 # by an AC_MSG_CHECKING/AC_MSG_RESULT pair.
 AC_DEFUN([gl_CACHE_VAL_SILENT],
 [
-  saved_as_echo_n="$as_echo_n"
-  as_echo_n=':'
-  AC_CACHE_VAL([$1], [$2])
-  as_echo_n="$saved_as_echo_n"
+  gl_SILENT([
+    AC_CACHE_VAL([$1], [$2])
+  ])
+])
+
+# gl_CONDITIONAL(conditional, condition)
+# is like AM_CONDITIONAL(conditional, condition), except that it does not
+# produce an error
+#   configure: error: conditional "..." was never defined.
+#   Usually this means the macro was only invoked conditionally.
+# when only invoked conditionally. Instead, in that case, both the _TRUE
+# and the _FALSE case are disabled.
+AC_DEFUN([gl_CONDITIONAL],
+[
+  pushdef([AC_CONFIG_COMMANDS_PRE], [:])dnl
+  AM_CONDITIONAL([$1], [$2])
+  popdef([AC_CONFIG_COMMANDS_PRE])dnl
+  if test -z "${[$1]_TRUE}" && test -z "${[$1]_FALSE}"; then
+    [$1]_TRUE='#'
+    [$1]_FALSE='#'
+  fi
+])
+
+# gl_CC_ALLOW_WARNINGS
+# sets and substitutes a variable GL_CFLAG_ALLOW_WARNINGS, to a $(CC) option
+# that reverts a preceding '-Werror' option, if available.
+# This is expected to be '-Wno-error' on gcc, clang (except clang/MSVC), xlclang
+# and empty otherwise.
+AC_DEFUN([gl_CC_ALLOW_WARNINGS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_CACHE_CHECK([for C compiler option to allow warnings],
+    [gl_cv_cc_wallow],
+    [rm -f conftest*
+     echo 'int dummy;' > conftest.c
+     AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -c conftest.c 2>conftest1.err]) >/dev/null
+     AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -Wno-error -c conftest.c 2>conftest2.err]) >/dev/null
+     dnl Test the number of error output lines, because AIX xlc accepts the
+     dnl option '-Wno-error', just to produce a warning
+     dnl "Option -Wno-error was incorrectly specified. The option will be ignored."
+     dnl afterwards.
+     if test $? = 0 && test `wc -l < conftest1.err` = `wc -l < conftest2.err`; then
+       gl_cv_cc_wallow='-Wno-error'
+     else
+       gl_cv_cc_wallow=none
+     fi
+     rm -f conftest*
+    ])
+  case "$gl_cv_cc_wallow" in
+    none) GL_CFLAG_ALLOW_WARNINGS='' ;;
+    *)    GL_CFLAG_ALLOW_WARNINGS="$gl_cv_cc_wallow" ;;
+  esac
+  AC_SUBST([GL_CFLAG_ALLOW_WARNINGS])
+])
+
+# gl_CXX_ALLOW_WARNINGS
+# sets and substitutes a variable GL_CXXFLAG_ALLOW_WARNINGS, to a $(CC) option
+# that reverts a preceding '-Werror' option, if available.
+AC_DEFUN([gl_CXX_ALLOW_WARNINGS],
+[
+  dnl Requires AC_PROG_CXX or gl_PROG_ANSI_CXX.
+  if test -n "$CXX" && test "$CXX" != no; then
+    AC_CACHE_CHECK([for C++ compiler option to allow warnings],
+      [gl_cv_cxx_wallow],
+      [rm -f conftest*
+       echo 'int dummy;' > conftest.cc
+       AC_TRY_COMMAND([${CXX-c++} $CXXFLAGS $CPPFLAGS -c conftest.cc 2>conftest1.err]) >/dev/null
+       AC_TRY_COMMAND([${CXX-c++} $CXXFLAGS $CPPFLAGS -Wno-error -c conftest.cc 2>conftest2.err]) >/dev/null
+       dnl Test the number of error output lines, because AIX xlC accepts the
+       dnl option '-Wno-error', just to produce a warning
+       dnl "Option -Wno-error was incorrectly specified. The option will be ignored."
+       dnl afterwards.
+       if test $? = 0 && test `wc -l < conftest1.err` = `wc -l < conftest2.err`; then
+         gl_cv_cxx_wallow='-Wno-error'
+       else
+         gl_cv_cxx_wallow=none
+       fi
+       rm -f conftest*
+      ])
+    case "$gl_cv_cxx_wallow" in
+      none) GL_CXXFLAG_ALLOW_WARNINGS='' ;;
+      *)    GL_CXXFLAG_ALLOW_WARNINGS="$gl_cv_cxx_wallow" ;;
+    esac
+  else
+    GL_CXXFLAG_ALLOW_WARNINGS=''
+  fi
+  AC_SUBST([GL_CXXFLAG_ALLOW_WARNINGS])
+])
+
+# gl_CC_GNULIB_WARNINGS
+# sets and substitutes a variable GL_CFLAG_GNULIB_WARNINGS, to a $(CC) option
+# set that enables or disables warnings as suitable for the Gnulib coding style.
+AC_DEFUN([gl_CC_GNULIB_WARNINGS],
+[
+  AC_REQUIRE([gl_CC_ALLOW_WARNINGS])
+  dnl Assume that the compiler supports -Wno-* options only if it also supports
+  dnl -Wno-error.
+  GL_CFLAG_GNULIB_WARNINGS=''
+  if test -n "$GL_CFLAG_ALLOW_WARNINGS"; then
+    dnl Enable these warning options:
+    dnl
+    dnl                                       GCC             clang
+    dnl -Wno-cast-qual                        >= 3            >= 3.9
+    dnl -Wno-conversion                       >= 3            >= 3.9
+    dnl -Wno-float-conversion                 >= 4.9          >= 3.9
+    dnl -Wno-float-equal                      >= 3            >= 3.9
+    dnl -Wimplicit-fallthrough                >= 7            >= 3.9
+    dnl -Wno-pedantic                         >= 4.8          >= 3.9
+    dnl -Wno-sign-compare                     >= 3            >= 3.9
+    dnl -Wno-sign-conversion                  >= 4.3          >= 3.9
+    dnl -Wno-type-limits                      >= 4.3          >= 3.9
+    dnl -Wno-undef                            >= 3            >= 3.9
+    dnl -Wno-unsuffixed-float-constants       >= 4.5
+    dnl -Wno-unused-function                  >= 3            >= 3.9
+    dnl -Wno-unused-parameter                 >= 3            >= 3.9
+    dnl
+    cat > conftest.c <<\EOF
+      #if __GNUC__ >= 3 || (__clang_major__ + (__clang_minor__ >= 9) > 3)
+      -Wno-cast-qual
+      -Wno-conversion
+      -Wno-float-equal
+      -Wno-sign-compare
+      -Wno-undef
+      -Wno-unused-function
+      -Wno-unused-parameter
+      #endif
+      #if __GNUC__ + (__GNUC_MINOR__ >= 9) > 4 || (__clang_major__ + (__clang_minor__ >= 9) > 3)
+      -Wno-float-conversion
+      #endif
+      #if __GNUC__ >= 7 || (__clang_major__ + (__clang_minor__ >= 9) > 3)
+      -Wimplicit-fallthrough
+      #endif
+      #if __GNUC__ + (__GNUC_MINOR__ >= 8) > 4 || (__clang_major__ + (__clang_minor__ >= 9) > 3)
+      -Wno-pedantic
+      #endif
+      #if __GNUC__ + (__GNUC_MINOR__ >= 3) > 4 || (__clang_major__ + (__clang_minor__ >= 9) > 3)
+      -Wno-sign-conversion
+      -Wno-type-limits
+      #endif
+      #if __GNUC__ + (__GNUC_MINOR__ >= 5) > 4
+      -Wno-unsuffixed-float-constants
+      #endif
+EOF
+    gl_command="$CC $CFLAGS $CPPFLAGS -E conftest.c > conftest.out"
+    if AC_TRY_EVAL([gl_command]); then
+      gl_options=`grep -v '#' conftest.out`
+      for word in $gl_options; do
+        GL_CFLAG_GNULIB_WARNINGS="$GL_CFLAG_GNULIB_WARNINGS $word"
+      done
+    fi
+    rm -f conftest.c conftest.out
+  fi
+  AC_SUBST([GL_CFLAG_GNULIB_WARNINGS])
+])
+
+dnl gl_CONDITIONAL_HEADER([foo.h])
+dnl takes a shell variable GL_GENERATE_FOO_H (with value true or false) as input
+dnl and produces
+dnl   - an AC_SUBSTed variable FOO_H that is either a file name or empty, based
+dnl     on whether GL_GENERATE_FOO_H is true or false,
+dnl   - an Automake conditional GL_GENERATE_FOO_H that evaluates to the value of
+dnl     the shell variable GL_GENERATE_FOO_H.
+AC_DEFUN([gl_CONDITIONAL_HEADER],
+[
+  m4_pushdef([gl_header_name], AS_TR_SH(m4_toupper($1)))
+  m4_pushdef([gl_generate_var], [GL_GENERATE_]AS_TR_SH(m4_toupper($1)))
+  m4_pushdef([gl_generate_cond], [GL_GENERATE_]AS_TR_SH(m4_toupper($1)))
+  case "$gl_generate_var" in
+    false) gl_header_name='' ;;
+    true)
+      dnl It is OK to use a .h file in lib/ from within tests/, but not vice
+      dnl versa.
+      if test -z "$gl_header_name"; then
+        gl_header_name="${gl_source_base_prefix}$1"
+      fi
+      ;;
+    *) echo "*** gl_generate_var is not set correctly" 1>&2; exit 1 ;;
+  esac
+  AC_SUBST(gl_header_name)
+  gl_CONDITIONAL(gl_generate_cond, [$gl_generate_var])
+  m4_popdef([gl_generate_cond])
+  m4_popdef([gl_generate_var])
+  m4_popdef([gl_header_name])
+])
+
+dnl Expands to some code for use in .c programs that, on native Windows, defines
+dnl the Microsoft deprecated alias function names to the underscore-prefixed
+dnl actual function names. With this macro, these function names are available
+dnl without linking with '-loldnames' and without generating warnings.
+dnl Usage: Use it after all system header files are included.
+dnl          #include <...>
+dnl          #include <...>
+dnl          ]GL_MDA_DEFINES[
+dnl          ...
+AC_DEFUN([GL_MDA_DEFINES],[
+AC_REQUIRE([_GL_MDA_DEFINES])
+[$gl_mda_defines]
+])
+AC_DEFUN([_GL_MDA_DEFINES],
+[gl_mda_defines='
+#if defined _WIN32 && !defined __CYGWIN__
+#define access    _access
+#define chdir     _chdir
+#define chmod     _chmod
+#define close     _close
+#define creat     _creat
+#define dup       _dup
+#define dup2      _dup2
+#define ecvt      _ecvt
+#define execl     _execl
+#define execle    _execle
+#define execlp    _execlp
+#define execv     _execv
+#define execve    _execve
+#define execvp    _execvp
+#define execvpe   _execvpe
+#define fcloseall _fcloseall
+#define fcvt      _fcvt
+#define fdopen    _fdopen
+#define fileno    _fileno
+#define gcvt      _gcvt
+#define getcwd    _getcwd
+#define getpid    _getpid
+#define getw      _getw
+#define isatty    _isatty
+#define j0        _j0
+#define j1        _j1
+#define jn        _jn
+#define lfind     _lfind
+#define lsearch   _lsearch
+#define lseek     _lseek
+#define memccpy   _memccpy
+#define mkdir     _mkdir
+#define mktemp    _mktemp
+#define open      _open
+#define putenv    _putenv
+#define putw      _putw
+#define read      _read
+#define rmdir     _rmdir
+#define strdup    _strdup
+#define swab      _swab
+#define tempnam   _tempnam
+#define tzset     _tzset
+#define umask     _umask
+#define unlink    _unlink
+#define utime     _utime
+#define wcsdup    _wcsdup
+#define write     _write
+#define y0        _y0
+#define y1        _y1
+#define yn        _yn
+#endif
+'
 ])
diff --git a/gl/m4/gnulib-comp.m4 b/gl/m4/gnulib-comp.m4
index 9a4f5027..644b9169 100644
--- a/gl/m4/gnulib-comp.m4
+++ b/gl/m4/gnulib-comp.m4
@@ -1,9 +1,9 @@
 # DO NOT EDIT! GENERATED AUTOMATICALLY!
-# Copyright (C) 2002-2013 Free Software Foundation, Inc.
+# Copyright (C) 2002-2023 Free Software Foundation, Inc.
 #
 # This file is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 3 of the License, or
+# the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This file is distributed in the hope that it will be useful,
@@ -12,7 +12,7 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
-# along with this file.  If not, see <http://www.gnu.org/licenses/>.
+# along with this file.  If not, see <https://www.gnu.org/licenses/>.
 #
 # As a special exception to the GNU General Public License,
 # this file may be distributed as part of a program that
@@ -37,50 +37,93 @@ AC_DEFUN([gl_EARLY],
   m4_pattern_allow([^gl_ES$])dnl a valid locale name
   m4_pattern_allow([^gl_LIBOBJS$])dnl a variable
   m4_pattern_allow([^gl_LTLIBOBJS$])dnl a variable
+
+  # Pre-early section.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   AC_REQUIRE([gl_PROG_AR_RANLIB])
-  AC_REQUIRE([AM_PROG_CC_C_O])
+
+  # Code from module absolute-header:
   # Code from module alloca-opt:
   # Code from module arpa_inet:
+  # Code from module assert-h:
+  # Code from module attribute:
   # Code from module base64:
+  # Code from module basename-lgpl:
   # Code from module btowc:
-  # Code from module configmake:
+  # Code from module builtin-expect:
+  # Code from module byteswap:
+  # Code from module c99:
+  # Code from module calloc-gnu:
+  # Code from module calloc-posix:
+  # Code from module cloexec:
+  # Code from module close:
+  # Code from module crypto/af_alg:
   # Code from module crypto/sha1:
+  # Code from module crypto/sha1-buffer:
   # Code from module dirname:
   # Code from module dirname-lgpl:
-  # Code from module dosname:
   # Code from module double-slash-root:
+  # Code from module dup2:
   # Code from module environ:
   # Code from module errno:
   # Code from module error:
   # Code from module exitfail:
   # Code from module extensions:
-  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   # Code from module extern-inline:
+  # Code from module fcntl:
+  # Code from module fcntl-h:
   # Code from module fd-hook:
+  # Code from module fflush:
+  AC_REQUIRE([gl_SET_LARGEFILE_SOURCE])
+  # Code from module filename:
   # Code from module float:
   # Code from module floorf:
+  # Code from module fopen:
+  # Code from module fopen-gnu:
+  # Code from module fpurge:
+  # Code from module freading:
+  # Code from module free-posix:
+  # Code from module fseek:
+  # Code from module fseeko:
+  AC_REQUIRE([gl_SET_LARGEFILE_SOURCE])
+  # Code from module fstat:
   # Code from module fsusage:
-  # Code from module full-read:
+  # Code from module ftell:
+  # Code from module ftello:
+  AC_REQUIRE([gl_SET_LARGEFILE_SOURCE])
+  # Code from module gen-header:
   # Code from module getaddrinfo:
+  # Code from module getdelim:
+  # Code from module getdtablesize:
   # Code from module gethostname:
+  # Code from module getline:
   # Code from module getloadavg:
   # Code from module getopt-gnu:
   # Code from module getopt-posix:
+  # Code from module getprogname:
   # Code from module gettext:
   # Code from module gettext-h:
+  # Code from module glibc-internal/dynarray:
+  # Code from module hard-locale:
   # Code from module havelib:
   # Code from module hostent:
+  # Code from module ialloc:
   # Code from module idpriv-droptemp:
+  # Code from module idx:
   # Code from module include_next:
   # Code from module inet_ntop:
   # Code from module intprops:
+  # Code from module inttypes-incomplete:
   # Code from module langinfo:
   # Code from module largefile:
   AC_REQUIRE([AC_SYS_LARGEFILE])
+  # Code from module libc-config:
+  # Code from module limits-h:
   # Code from module localcharset:
   # Code from module locale:
   # Code from module localeconv:
   # Code from module lock:
+  # Code from module lseek:
   # Code from module malloc-gnu:
   # Code from module malloc-posix:
   # Code from module malloca:
@@ -89,6 +132,7 @@ AC_DEFUN([gl_EARLY],
   # Code from module mbsinit:
   # Code from module mbtowc:
   # Code from module memchr:
+  # Code from module minmax:
   # Code from module mktime:
   # Code from module mktime-internal:
   # Code from module mountlist:
@@ -99,11 +143,15 @@ AC_DEFUN([gl_EARLY],
   # Code from module netinet_in:
   # Code from module nl_langinfo:
   # Code from module nocrash:
-  # Code from module read:
+  # Code from module open:
+  # Code from module pathmax:
+  # Code from module realloc-gnu:
+  # Code from module realloc-posix:
+  # Code from module reallocarray:
   # Code from module regex:
-  # Code from module safe-read:
   # Code from module servent:
   # Code from module setenv:
+  # Code from module setlocale-null:
   # Code from module size_max:
   # Code from module snippet/_Noreturn:
   # Code from module snippet/arg-nonnull:
@@ -114,8 +162,12 @@ AC_DEFUN([gl_EARLY],
   # Code from module sockets:
   # Code from module socklen:
   # Code from module ssize_t:
+  # Code from module stat:
+  # Code from module stat-time:
+  # Code from module std-gnu11:
   # Code from module stdalign:
   # Code from module stdbool:
+  # Code from module stdckdint:
   # Code from module stddef:
   # Code from module stdint:
   # Code from module stdio:
@@ -128,11 +180,10 @@ AC_DEFUN([gl_EARLY],
   # Code from module strerror-override:
   # Code from module string:
   # Code from module strings:
-  # Code from module strndup:
-  # Code from module strnlen:
   # Code from module strsep:
   # Code from module strstr-simple:
   # Code from module sys_socket:
+  # Code from module sys_stat:
   # Code from module sys_types:
   # Code from module sys_uio:
   # Code from module threadlib:
@@ -141,7 +192,9 @@ AC_DEFUN([gl_EARLY],
   # Code from module time_r:
   # Code from module timegm:
   # Code from module unistd:
+  # Code from module unlocked-io-internal:
   # Code from module unsetenv:
+  # Code from module vararrays:
   # Code from module vasnprintf:
   # Code from module vasprintf:
   # Code from module verify:
@@ -149,11 +202,14 @@ AC_DEFUN([gl_EARLY],
   # Code from module wchar:
   # Code from module wcrtomb:
   # Code from module wctype-h:
+  # Code from module windows-mutex:
+  # Code from module windows-once:
+  # Code from module windows-recmutex:
+  # Code from module windows-rwlock:
   # Code from module xalloc:
   # Code from module xalloc-die:
   # Code from module xalloc-oversized:
   # Code from module xsize:
-  # Code from module xstrndup:
 ])
 
 # This macro should be invoked from ./configure.ac, in the section
@@ -170,154 +226,303 @@ AC_DEFUN([gl_INIT],
   m4_pushdef([AC_LIBSOURCES], m4_defn([gl_LIBSOURCES]))
   m4_pushdef([gl_LIBSOURCES_LIST], [])
   m4_pushdef([gl_LIBSOURCES_DIR], [])
+  m4_pushdef([GL_MACRO_PREFIX], [gl])
+  m4_pushdef([GL_MODULE_INDICATOR_PREFIX], [GL])
   gl_COMMON
   gl_source_base='gl'
+  gl_source_base_prefix=
   gl_FUNC_ALLOCA
-  gl_HEADER_ARPA_INET
+  gl_CONDITIONAL_HEADER([alloca.h])
+  AC_PROG_MKDIR_P
+  gl_ARPA_INET_H
+  gl_ARPA_INET_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
+  gl_ASSERT_H
+  gl_CONDITIONAL_HEADER([assert.h])
   AC_PROG_MKDIR_P
   gl_FUNC_BASE64
   gl_FUNC_BTOWC
-  if test $HAVE_BTOWC = 0 || test $REPLACE_BTOWC = 1; then
-    AC_LIBOBJ([btowc])
+  gl_CONDITIONAL([GL_COND_OBJ_BTOWC],
+                 [test $HAVE_BTOWC = 0 || test $REPLACE_BTOWC = 1])
+  AM_COND_IF([GL_COND_OBJ_BTOWC], [
     gl_PREREQ_BTOWC
-  fi
+  ])
   gl_WCHAR_MODULE_INDICATOR([btowc])
-  gl_CONFIGMAKE_PREP
+  gl___BUILTIN_EXPECT
+  gl_BYTESWAP
+  gl_CONDITIONAL_HEADER([byteswap.h])
+  AC_PROG_MKDIR_P
+  gl_FUNC_CALLOC_GNU
+  if test $REPLACE_CALLOC_FOR_CALLOC_GNU = 1; then
+    AC_LIBOBJ([calloc])
+  fi
+  gl_STDLIB_MODULE_INDICATOR([calloc-gnu])
+  gl_FUNC_CALLOC_POSIX
+  if test $REPLACE_CALLOC_FOR_CALLOC_POSIX = 1; then
+    AC_LIBOBJ([calloc])
+  fi
+  gl_STDLIB_MODULE_INDICATOR([calloc-posix])
+  gl_MODULE_INDICATOR_FOR_TESTS([cloexec])
+  gl_FUNC_CLOSE
+  gl_CONDITIONAL([GL_COND_OBJ_CLOSE], [test $REPLACE_CLOSE = 1])
+  gl_UNISTD_MODULE_INDICATOR([close])
+  gl_AF_ALG
+  AC_REQUIRE([AC_C_RESTRICT])
   gl_SHA1
-  gl_DIRNAME
   gl_MODULE_INDICATOR([dirname])
-  gl_DIRNAME_LGPL
   gl_DOUBLE_SLASH_ROOT
+  gl_FUNC_DUP2
+  gl_CONDITIONAL([GL_COND_OBJ_DUP2], [test $REPLACE_DUP2 = 1])
+  AM_COND_IF([GL_COND_OBJ_DUP2], [
+    gl_PREREQ_DUP2
+  ])
+  gl_UNISTD_MODULE_INDICATOR([dup2])
   gl_ENVIRON
   gl_UNISTD_MODULE_INDICATOR([environ])
   gl_HEADER_ERRNO_H
+  gl_CONDITIONAL_HEADER([errno.h])
+  AC_PROG_MKDIR_P
   gl_ERROR
-  if test $ac_cv_lib_error_at_line = no; then
-    AC_LIBOBJ([error])
+  gl_CONDITIONAL([GL_COND_OBJ_ERROR], [test "$ac_cv_lib_error_at_line" = no])
+  AM_COND_IF([GL_COND_OBJ_ERROR], [
     gl_PREREQ_ERROR
-  fi
+  ])
   m4_ifdef([AM_XGETTEXT_OPTION],
     [AM_][XGETTEXT_OPTION([--flag=error:3:c-format])
      AM_][XGETTEXT_OPTION([--flag=error_at_line:5:c-format])])
   AC_REQUIRE([gl_EXTERN_INLINE])
+  gl_FUNC_FCNTL
+  gl_CONDITIONAL([GL_COND_OBJ_FCNTL],
+                 [test $HAVE_FCNTL = 0 || test $REPLACE_FCNTL = 1])
+  gl_FCNTL_MODULE_INDICATOR([fcntl])
+  gl_FCNTL_H
+  gl_FCNTL_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
+  gl_FUNC_FFLUSH
+  gl_CONDITIONAL([GL_COND_OBJ_FFLUSH], [test $REPLACE_FFLUSH = 1])
+  AM_COND_IF([GL_COND_OBJ_FFLUSH], [
+    gl_PREREQ_FFLUSH
+  ])
+  gl_MODULE_INDICATOR([fflush])
+  gl_STDIO_MODULE_INDICATOR([fflush])
   gl_FLOAT_H
-  if test $REPLACE_FLOAT_LDBL = 1; then
-    AC_LIBOBJ([float])
-  fi
-  if test $REPLACE_ITOLD = 1; then
-    AC_LIBOBJ([itold])
-  fi
+  gl_CONDITIONAL_HEADER([float.h])
+  AC_PROG_MKDIR_P
+  gl_CONDITIONAL([GL_COND_OBJ_FLOAT], [test $REPLACE_FLOAT_LDBL = 1])
+  gl_CONDITIONAL([GL_COND_OBJ_ITOLD], [test $REPLACE_ITOLD = 1])
   gl_FUNC_FLOORF
-  if test $HAVE_DECL_FLOORF = 0 || test $REPLACE_FLOORF = 1; then
-    AC_LIBOBJ([floorf])
-  fi
+  gl_CONDITIONAL([GL_COND_OBJ_FLOORF],
+                 [test $HAVE_DECL_FLOORF = 0 || test $REPLACE_FLOORF = 1])
   gl_MATH_MODULE_INDICATOR([floorf])
+  gl_FUNC_FOPEN
+  if test $REPLACE_FOPEN = 1; then
+    AC_LIBOBJ([fopen])
+    gl_PREREQ_FOPEN
+  fi
+  gl_STDIO_MODULE_INDICATOR([fopen])
+  gl_FUNC_FOPEN_GNU
+  if test $REPLACE_FOPEN_FOR_FOPEN_GNU = 1; then
+    AC_LIBOBJ([fopen])
+    gl_PREREQ_FOPEN
+  fi
+  gl_MODULE_INDICATOR([fopen-gnu])
+  gl_STDIO_MODULE_INDICATOR([fopen-gnu])
+  gl_FUNC_FPURGE
+  gl_CONDITIONAL([GL_COND_OBJ_FPURGE],
+                 [test $HAVE_FPURGE = 0 || test $REPLACE_FPURGE = 1])
+  gl_STDIO_MODULE_INDICATOR([fpurge])
+  gl_FUNC_FREADING
+  gl_FUNC_FREE
+  gl_CONDITIONAL([GL_COND_OBJ_FREE], [test $REPLACE_FREE = 1])
+  AM_COND_IF([GL_COND_OBJ_FREE], [
+    gl_PREREQ_FREE
+  ])
+  gl_STDLIB_MODULE_INDICATOR([free-posix])
+  gl_FUNC_FSEEK
+  gl_CONDITIONAL([GL_COND_OBJ_FSEEK], [test $REPLACE_FSEEK = 1])
+  gl_STDIO_MODULE_INDICATOR([fseek])
+  gl_FUNC_FSEEKO
+  gl_CONDITIONAL([GL_COND_OBJ_FSEEKO],
+                 [test $HAVE_FSEEKO = 0 || test $REPLACE_FSEEKO = 1])
+  AM_COND_IF([GL_COND_OBJ_FSEEKO], [
+    gl_PREREQ_FSEEKO
+  ])
+  gl_STDIO_MODULE_INDICATOR([fseeko])
+  gl_FUNC_FSTAT
+  gl_CONDITIONAL([GL_COND_OBJ_FSTAT], [test $REPLACE_FSTAT = 1])
+  AM_COND_IF([GL_COND_OBJ_FSTAT], [
+    case "$host_os" in
+      mingw*)
+        AC_LIBOBJ([stat-w32])
+        ;;
+    esac
+    gl_PREREQ_FSTAT
+  ])
+  gl_SYS_STAT_MODULE_INDICATOR([fstat])
   gl_FSUSAGE
-  if test $gl_cv_fs_space = yes; then
-    AC_LIBOBJ([fsusage])
+  gl_CONDITIONAL([GL_COND_OBJ_FSUSAGE], [test $gl_cv_fs_space = yes])
+  AM_COND_IF([GL_COND_OBJ_FSUSAGE], [
     gl_PREREQ_FSUSAGE_EXTRA
-  fi
+  ])
+  gl_FUNC_FTELL
+  gl_CONDITIONAL([GL_COND_OBJ_FTELL], [test $REPLACE_FTELL = 1])
+  gl_STDIO_MODULE_INDICATOR([ftell])
+  gl_FUNC_FTELLO
+  gl_CONDITIONAL([GL_COND_OBJ_FTELLO],
+                 [test $HAVE_FTELLO = 0 || test $REPLACE_FTELLO = 1])
+  AM_COND_IF([GL_COND_OBJ_FTELLO], [
+    gl_PREREQ_FTELLO
+  ])
+  gl_STDIO_MODULE_INDICATOR([ftello])
   gl_GETADDRINFO
-  if test $HAVE_GETADDRINFO = 0; then
-    AC_LIBOBJ([getaddrinfo])
-  fi
-  if test $HAVE_DECL_GAI_STRERROR = 0 || test $REPLACE_GAI_STRERROR = 1; then
-    AC_LIBOBJ([gai_strerror])
-  fi
+  gl_CONDITIONAL([GL_COND_OBJ_GETADDRINFO],
+                 [test $HAVE_GETADDRINFO = 0 || test $REPLACE_GETADDRINFO = 1])
+  gl_CONDITIONAL([GL_COND_OBJ_GAI_STRERROR],
+                 [test $HAVE_DECL_GAI_STRERROR = 0 || test $REPLACE_GAI_STRERROR = 1])
   gl_NETDB_MODULE_INDICATOR([getaddrinfo])
+  gl_FUNC_GETDELIM
+  gl_CONDITIONAL([GL_COND_OBJ_GETDELIM],
+                 [test $HAVE_GETDELIM = 0 || test $REPLACE_GETDELIM = 1])
+  AM_COND_IF([GL_COND_OBJ_GETDELIM], [
+    gl_PREREQ_GETDELIM
+  ])
+  gl_STDIO_MODULE_INDICATOR([getdelim])
+  gl_FUNC_GETDTABLESIZE
+  gl_CONDITIONAL([GL_COND_OBJ_GETDTABLESIZE],
+                 [test $HAVE_GETDTABLESIZE = 0 || test $REPLACE_GETDTABLESIZE = 1])
+  AM_COND_IF([GL_COND_OBJ_GETDTABLESIZE], [
+    gl_PREREQ_GETDTABLESIZE
+  ])
+  gl_UNISTD_MODULE_INDICATOR([getdtablesize])
   gl_FUNC_GETHOSTNAME
-  if test $HAVE_GETHOSTNAME = 0; then
-    AC_LIBOBJ([gethostname])
+  gl_CONDITIONAL([GL_COND_OBJ_GETHOSTNAME], [test $HAVE_GETHOSTNAME = 0])
+  AM_COND_IF([GL_COND_OBJ_GETHOSTNAME], [
     gl_PREREQ_GETHOSTNAME
-  fi
+  ])
   gl_UNISTD_MODULE_INDICATOR([gethostname])
+  gl_FUNC_GETLINE
+  gl_CONDITIONAL([GL_COND_OBJ_GETLINE], [test $REPLACE_GETLINE = 1])
+  AM_COND_IF([GL_COND_OBJ_GETLINE], [
+    gl_PREREQ_GETLINE
+  ])
+  gl_STDIO_MODULE_INDICATOR([getline])
+  AC_REQUIRE([AC_CANONICAL_HOST])
   gl_GETLOADAVG
-  if test $HAVE_GETLOADAVG = 0; then
-    AC_LIBOBJ([getloadavg])
+  gl_CONDITIONAL([GL_COND_OBJ_GETLOADAVG], [test $HAVE_GETLOADAVG = 0])
+  AM_COND_IF([GL_COND_OBJ_GETLOADAVG], [
     gl_PREREQ_GETLOADAVG
-  fi
+  ])
   gl_STDLIB_MODULE_INDICATOR([getloadavg])
   gl_FUNC_GETOPT_GNU
-  if test $REPLACE_GETOPT = 1; then
-    AC_LIBOBJ([getopt])
-    AC_LIBOBJ([getopt1])
-    gl_PREREQ_GETOPT
-    dnl Arrange for unistd.h to include getopt.h.
-    GNULIB_GL_UNISTD_H_GETOPT=1
-  fi
-  AC_SUBST([GNULIB_GL_UNISTD_H_GETOPT])
-  gl_MODULE_INDICATOR_FOR_TESTS([getopt-gnu])
+  dnl Because of the way gl_FUNC_GETOPT_GNU is implemented (the gl_getopt_required
+  dnl mechanism), there is no need to do any AC_LIBOBJ or AC_SUBST here; they are
+  dnl done in the getopt-posix module.
   gl_FUNC_GETOPT_POSIX
-  if test $REPLACE_GETOPT = 1; then
-    AC_LIBOBJ([getopt])
-    AC_LIBOBJ([getopt1])
-    gl_PREREQ_GETOPT
-    dnl Arrange for unistd.h to include getopt.h.
-    GNULIB_GL_UNISTD_H_GETOPT=1
-  fi
-  AC_SUBST([GNULIB_GL_UNISTD_H_GETOPT])
+  gl_CONDITIONAL_HEADER([getopt.h])
+  gl_CONDITIONAL_HEADER([getopt-cdefs.h])
+  AC_PROG_MKDIR_P
+  gl_CONDITIONAL([GL_COND_OBJ_GETOPT], [test $REPLACE_GETOPT = 1])
+  AM_COND_IF([GL_COND_OBJ_GETOPT], [
+    dnl Define the substituted variable GNULIB_UNISTD_H_GETOPT to 1.
+    gl_UNISTD_H_REQUIRE_DEFAULTS
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_UNISTD_H_GETOPT], [1])
+  ])
+  gl_UNISTD_MODULE_INDICATOR([getopt-posix])
+  gl_FUNC_GETPROGNAME
   dnl you must add AM_GNU_GETTEXT([external]) or similar to configure.ac.
-  AM_GNU_GETTEXT_VERSION([0.18.1])
+  AM_GNU_GETTEXT_VERSION([0.20])
   AC_SUBST([LIBINTL])
   AC_SUBST([LTLIBINTL])
+  AC_PROG_MKDIR_P
+  AC_REQUIRE([gl_FUNC_SETLOCALE_NULL])
+  LIB_HARD_LOCALE="$LIB_SETLOCALE_NULL"
+  AC_SUBST([LIB_HARD_LOCALE])
+  AC_DEFUN([gl_HAVE_MODULE_HAVELIB])
   gl_HOSTENT
   gl_IDPRIV
   gl_FUNC_INET_NTOP
-  if test $HAVE_INET_NTOP = 0 || test $REPLACE_INET_NTOP = 1; then
-    AC_LIBOBJ([inet_ntop])
+  gl_CONDITIONAL([GL_COND_OBJ_INET_NTOP],
+                 [test $HAVE_INET_NTOP = 0 || test $REPLACE_INET_NTOP = 1])
+  AM_COND_IF([GL_COND_OBJ_INET_NTOP], [
     gl_PREREQ_INET_NTOP
-  fi
+  ])
   gl_ARPA_INET_MODULE_INDICATOR([inet_ntop])
+  gl_INTTYPES_INCOMPLETE
+  gl_INTTYPES_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
   gl_LANGINFO_H
+  gl_LANGINFO_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
   AC_REQUIRE([gl_LARGEFILE])
+  gl___INLINE
+  gl_LIMITS_H
+  gl_CONDITIONAL_HEADER([limits.h])
+  AC_PROG_MKDIR_P
   gl_LOCALCHARSET
-  LOCALCHARSET_TESTS_ENVIRONMENT="CHARSETALIASDIR=\"\$(abs_top_builddir)/$gl_source_base\""
+  dnl For backward compatibility. Some packages still use this.
+  LOCALCHARSET_TESTS_ENVIRONMENT=
   AC_SUBST([LOCALCHARSET_TESTS_ENVIRONMENT])
   gl_LOCALE_H
+  gl_LOCALE_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
   gl_FUNC_LOCALECONV
-  if test $REPLACE_LOCALECONV = 1; then
-    AC_LIBOBJ([localeconv])
+  gl_CONDITIONAL([GL_COND_OBJ_LOCALECONV], [test $REPLACE_LOCALECONV = 1])
+  AM_COND_IF([GL_COND_OBJ_LOCALECONV], [
     gl_PREREQ_LOCALECONV
-  fi
+  ])
   gl_LOCALE_MODULE_INDICATOR([localeconv])
   gl_LOCK
   gl_MODULE_INDICATOR([lock])
+  gl_FUNC_LSEEK
+  gl_CONDITIONAL([GL_COND_OBJ_LSEEK], [test $REPLACE_LSEEK = 1])
+  gl_UNISTD_MODULE_INDICATOR([lseek])
   gl_FUNC_MALLOC_GNU
-  if test $REPLACE_MALLOC = 1; then
+  if test $REPLACE_MALLOC_FOR_MALLOC_GNU = 1; then
     AC_LIBOBJ([malloc])
   fi
-  gl_MODULE_INDICATOR([malloc-gnu])
-  gl_FUNC_MALLOC_POSIX
-  if test $REPLACE_MALLOC = 1; then
+  gl_STDLIB_MODULE_INDICATOR([malloc-gnu])
+  AC_REQUIRE([gl_FUNC_MALLOC_POSIX])
+  if test $REPLACE_MALLOC_FOR_MALLOC_POSIX = 1; then
     AC_LIBOBJ([malloc])
   fi
   gl_STDLIB_MODULE_INDICATOR([malloc-posix])
   gl_MALLOCA
   gl_MATH_H
+  gl_MATH_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
   gl_FUNC_MBRTOWC
-  if test $HAVE_MBRTOWC = 0 || test $REPLACE_MBRTOWC = 1; then
-    AC_LIBOBJ([mbrtowc])
+  gl_CONDITIONAL([GL_COND_OBJ_MBRTOWC],
+                 [test $HAVE_MBRTOWC = 0 || test $REPLACE_MBRTOWC = 1])
+  AM_COND_IF([GL_COND_OBJ_MBRTOWC], [
+    if test $REPLACE_MBSTATE_T = 1; then
+      AC_LIBOBJ([lc-charset-dispatch])
+      AC_LIBOBJ([mbtowc-lock])
+      gl_PREREQ_MBTOWC_LOCK
+    fi
     gl_PREREQ_MBRTOWC
-  fi
+  ])
   gl_WCHAR_MODULE_INDICATOR([mbrtowc])
   gl_FUNC_MBSINIT
-  if test $HAVE_MBSINIT = 0 || test $REPLACE_MBSINIT = 1; then
-    AC_LIBOBJ([mbsinit])
+  gl_CONDITIONAL([GL_COND_OBJ_MBSINIT],
+                 [test $HAVE_MBSINIT = 0 || test $REPLACE_MBSINIT = 1])
+  AM_COND_IF([GL_COND_OBJ_MBSINIT], [
     gl_PREREQ_MBSINIT
-  fi
+  ])
   gl_WCHAR_MODULE_INDICATOR([mbsinit])
   gl_FUNC_MBTOWC
-  if test $REPLACE_MBTOWC = 1; then
-    AC_LIBOBJ([mbtowc])
+  gl_CONDITIONAL([GL_COND_OBJ_MBTOWC],
+                 [test $HAVE_MBTOWC = 0 || test $REPLACE_MBTOWC = 1])
+  AM_COND_IF([GL_COND_OBJ_MBTOWC], [
     gl_PREREQ_MBTOWC
-  fi
+  ])
   gl_STDLIB_MODULE_INDICATOR([mbtowc])
   gl_FUNC_MEMCHR
-  if test $HAVE_MEMCHR = 0 || test $REPLACE_MEMCHR = 1; then
-    AC_LIBOBJ([memchr])
+  gl_CONDITIONAL([GL_COND_OBJ_MEMCHR], [test $REPLACE_MEMCHR = 1])
+  AM_COND_IF([GL_COND_OBJ_MEMCHR], [
     gl_PREREQ_MEMCHR
-  fi
+  ])
   gl_STRING_MODULE_INDICATOR([memchr])
+  gl_MINMAX
   gl_FUNC_MKTIME
   if test $REPLACE_MKTIME = 1; then
     AC_LIBOBJ([mktime])
@@ -325,73 +530,162 @@ AC_DEFUN([gl_INIT],
   fi
   gl_TIME_MODULE_INDICATOR([mktime])
   gl_FUNC_MKTIME_INTERNAL
-  if test $REPLACE_MKTIME = 1; then
+  if test $WANT_MKTIME_INTERNAL = 1; then
     AC_LIBOBJ([mktime])
     gl_PREREQ_MKTIME
   fi
   gl_MOUNTLIST
-  if test $gl_cv_list_mounted_fs = yes; then
-    AC_LIBOBJ([mountlist])
+  gl_CONDITIONAL([GL_COND_OBJ_MOUNTLIST], [test $gl_cv_list_mounted_fs = yes])
+  AM_COND_IF([GL_COND_OBJ_MOUNTLIST], [
     gl_PREREQ_MOUNTLIST_EXTRA
-  fi
-  gl_MSVC_INVAL
-  if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
-    AC_LIBOBJ([msvc-inval])
-  fi
-  gl_MSVC_NOTHROW
-  if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
-    AC_LIBOBJ([msvc-nothrow])
-  fi
+  ])
+  AC_REQUIRE([gl_MSVC_INVAL])
+  gl_CONDITIONAL([GL_COND_OBJ_MSVC_INVAL],
+                 [test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1])
+  AC_REQUIRE([gl_MSVC_NOTHROW])
+  gl_CONDITIONAL([GL_COND_OBJ_MSVC_NOTHROW],
+                 [test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1])
+  gl_MODULE_INDICATOR([msvc-nothrow])
   gl_MULTIARCH
-  gl_HEADER_NETDB
+  gl_NETDB_H
+  gl_NETDB_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
   gl_HEADER_NETINET_IN
+  gl_CONDITIONAL_HEADER([netinet/in.h])
   AC_PROG_MKDIR_P
   gl_FUNC_NL_LANGINFO
-  if test $HAVE_NL_LANGINFO = 0 || test $REPLACE_NL_LANGINFO = 1; then
-    AC_LIBOBJ([nl_langinfo])
+  gl_CONDITIONAL([GL_COND_OBJ_NL_LANGINFO],
+                 [test $HAVE_NL_LANGINFO = 0 || test $REPLACE_NL_LANGINFO = 1])
+  gl_CONDITIONAL([GL_COND_OBJ_NL_LANGINFO_LOCK],
+                 [test $REPLACE_NL_LANGINFO = 1 && test $NL_LANGINFO_MTSAFE = 0])
+  if test $REPLACE_NL_LANGINFO = 1 && test $NL_LANGINFO_MTSAFE = 0; then
+    gl_PREREQ_NL_LANGINFO_LOCK
   fi
   gl_LANGINFO_MODULE_INDICATOR([nl_langinfo])
-  gl_FUNC_READ
-  if test $REPLACE_READ = 1; then
-    AC_LIBOBJ([read])
-    gl_PREREQ_READ
+  gl_FUNC_OPEN
+  gl_CONDITIONAL([GL_COND_OBJ_OPEN], [test $REPLACE_OPEN = 1])
+  AM_COND_IF([GL_COND_OBJ_OPEN], [
+    gl_PREREQ_OPEN
+  ])
+  gl_FCNTL_MODULE_INDICATOR([open])
+  gl_PATHMAX
+  gl_FUNC_REALLOC_GNU
+  if test $REPLACE_REALLOC_FOR_REALLOC_GNU = 1; then
+    AC_LIBOBJ([realloc])
+  fi
+  gl_STDLIB_MODULE_INDICATOR([realloc-gnu])
+  gl_FUNC_REALLOC_POSIX
+  if test $REPLACE_REALLOC_FOR_REALLOC_POSIX = 1; then
+    AC_LIBOBJ([realloc])
   fi
-  gl_UNISTD_MODULE_INDICATOR([read])
+  gl_STDLIB_MODULE_INDICATOR([realloc-posix])
+  gl_FUNC_REALLOCARRAY
+  gl_CONDITIONAL([GL_COND_OBJ_REALLOCARRAY],
+                 [test $HAVE_REALLOCARRAY = 0 || test $REPLACE_REALLOCARRAY = 1])
+  AM_COND_IF([GL_COND_OBJ_REALLOCARRAY], [
+    gl_PREREQ_REALLOCARRAY
+  ])
+  gl_MODULE_INDICATOR([reallocarray])
+  gl_STDLIB_MODULE_INDICATOR([reallocarray])
   gl_REGEX
-  if test $ac_use_included_regex = yes; then
-    AC_LIBOBJ([regex])
+  gl_CONDITIONAL([GL_COND_OBJ_REGEX], [test $ac_use_included_regex = yes])
+  AM_COND_IF([GL_COND_OBJ_REGEX], [
     gl_PREREQ_REGEX
-  fi
-  gl_PREREQ_SAFE_READ
+  ])
   gl_SERVENT
   gl_FUNC_SETENV
-  if test $HAVE_SETENV = 0 || test $REPLACE_SETENV = 1; then
-    AC_LIBOBJ([setenv])
-  fi
+  gl_CONDITIONAL([GL_COND_OBJ_SETENV],
+                 [test $HAVE_SETENV = 0 || test $REPLACE_SETENV = 1])
   gl_STDLIB_MODULE_INDICATOR([setenv])
+  gl_FUNC_SETLOCALE_NULL
+  gl_CONDITIONAL([GL_COND_OBJ_SETLOCALE_LOCK],
+                 [test $SETLOCALE_NULL_ALL_MTSAFE = 0 || test $SETLOCALE_NULL_ONE_MTSAFE = 0])
+  AM_COND_IF([GL_COND_OBJ_SETLOCALE_LOCK], [
+    gl_PREREQ_SETLOCALE_LOCK
+  ])
+  gl_LOCALE_MODULE_INDICATOR([setlocale_null])
   gl_SIZE_MAX
   gl_FUNC_SNPRINTF
   gl_STDIO_MODULE_INDICATOR([snprintf])
   gl_MODULE_INDICATOR([snprintf])
-  gl_SOCKETLIB
-  gl_SOCKETS
+  AC_REQUIRE([gl_SOCKETLIB])
+  AC_REQUIRE([gl_SOCKETS])
   gl_TYPE_SOCKLEN_T
   gt_TYPE_SSIZE_T
+  gl_FUNC_STAT
+  gl_CONDITIONAL([GL_COND_OBJ_STAT], [test $REPLACE_STAT = 1])
+  AM_COND_IF([GL_COND_OBJ_STAT], [
+    case "$host_os" in
+      mingw*)
+        AC_LIBOBJ([stat-w32])
+        ;;
+    esac
+    gl_PREREQ_STAT
+  ])
+  gl_SYS_STAT_MODULE_INDICATOR([stat])
+  gl_STAT_TIME
+  gl_STAT_BIRTHTIME
   gl_STDALIGN_H
-  AM_STDBOOL_H
+  gl_CONDITIONAL_HEADER([stdalign.h])
+  AC_PROG_MKDIR_P
+  gl_C_BOOL
+  AC_CHECK_HEADERS_ONCE([stdckdint.h])
+  if test $ac_cv_header_stdckdint_h = yes; then
+    GL_GENERATE_STDCKDINT_H=false
+  else
+    GL_GENERATE_STDCKDINT_H=true
+  fi
+  gl_CONDITIONAL_HEADER([stdckdint.h])
+  AC_PROG_MKDIR_P
   gl_STDDEF_H
+  gl_STDDEF_H_REQUIRE_DEFAULTS
+  gl_CONDITIONAL_HEADER([stddef.h])
+  AC_PROG_MKDIR_P
   gl_STDINT_H
+  gl_CONDITIONAL_HEADER([stdint.h])
+  dnl Because of gl_REPLACE_LIMITS_H:
+  gl_CONDITIONAL_HEADER([limits.h])
+  AC_PROG_MKDIR_P
   gl_STDIO_H
+  gl_STDIO_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
+  gl_CONDITIONAL([GL_COND_OBJ_STDIO_READ], [test $REPLACE_STDIO_READ_FUNCS = 1])
+  gl_CONDITIONAL([GL_COND_OBJ_STDIO_WRITE], [test $REPLACE_STDIO_WRITE_FUNCS = 1])
+  dnl No need to create extra modules for these functions. Everyone who uses
+  dnl <stdio.h> likely needs them.
+  gl_STDIO_MODULE_INDICATOR([fscanf])
+  gl_MODULE_INDICATOR([fscanf])
+  gl_STDIO_MODULE_INDICATOR([scanf])
+  gl_MODULE_INDICATOR([scanf])
+  gl_STDIO_MODULE_INDICATOR([fgetc])
+  gl_STDIO_MODULE_INDICATOR([getc])
+  gl_STDIO_MODULE_INDICATOR([getchar])
+  gl_STDIO_MODULE_INDICATOR([fgets])
+  gl_STDIO_MODULE_INDICATOR([fread])
+  dnl No need to create extra modules for these functions. Everyone who uses
+  dnl <stdio.h> likely needs them.
+  gl_STDIO_MODULE_INDICATOR([fprintf])
+  gl_STDIO_MODULE_INDICATOR([printf])
+  gl_STDIO_MODULE_INDICATOR([vfprintf])
+  gl_STDIO_MODULE_INDICATOR([vprintf])
+  gl_STDIO_MODULE_INDICATOR([fputc])
+  gl_STDIO_MODULE_INDICATOR([putc])
+  gl_STDIO_MODULE_INDICATOR([putchar])
+  gl_STDIO_MODULE_INDICATOR([fputs])
+  gl_STDIO_MODULE_INDICATOR([puts])
+  gl_STDIO_MODULE_INDICATOR([fwrite])
   gl_STDLIB_H
+  gl_STDLIB_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
   gl_STRCASE
-  if test $HAVE_STRCASECMP = 0; then
-    AC_LIBOBJ([strcasecmp])
+  gl_CONDITIONAL([GL_COND_OBJ_STRCASECMP], [test $HAVE_STRCASECMP = 0])
+  AM_COND_IF([GL_COND_OBJ_STRCASECMP], [
     gl_PREREQ_STRCASECMP
-  fi
-  if test $HAVE_STRNCASECMP = 0; then
-    AC_LIBOBJ([strncasecmp])
+  ])
+  gl_CONDITIONAL([GL_COND_OBJ_STRNCASECMP], [test $HAVE_STRNCASECMP = 0])
+  AM_COND_IF([GL_COND_OBJ_STRNCASECMP], [
     gl_PREREQ_STRNCASECMP
-  fi
+  ])
   gl_FUNC_STRCASESTR
   if test $HAVE_STRCASESTR = 0 || test $REPLACE_STRCASESTR = 1; then
     AC_LIBOBJ([strcasestr])
@@ -404,68 +698,76 @@ AC_DEFUN([gl_INIT],
   fi
   gl_STRING_MODULE_INDICATOR([strcasestr])
   gl_FUNC_STRERROR
-  if test $REPLACE_STRERROR = 1; then
-    AC_LIBOBJ([strerror])
-  fi
+  gl_CONDITIONAL([GL_COND_OBJ_STRERROR], [test $REPLACE_STRERROR = 1])
   gl_MODULE_INDICATOR([strerror])
   gl_STRING_MODULE_INDICATOR([strerror])
   AC_REQUIRE([gl_HEADER_ERRNO_H])
   AC_REQUIRE([gl_FUNC_STRERROR_0])
-  if test -n "$ERRNO_H" || test $REPLACE_STRERROR_0 = 1; then
-    AC_LIBOBJ([strerror-override])
+  gl_CONDITIONAL([GL_COND_OBJ_STRERROR_OVERRIDE],
+                 [test -n "$ERRNO_H" || test $REPLACE_STRERROR_0 = 1])
+  AM_COND_IF([GL_COND_OBJ_STRERROR_OVERRIDE], [
     gl_PREREQ_SYS_H_WINSOCK2
-  fi
-  gl_HEADER_STRING_H
-  gl_HEADER_STRINGS_H
-  gl_FUNC_STRNDUP
-  if test $HAVE_STRNDUP = 0 || test $REPLACE_STRNDUP = 1; then
-    AC_LIBOBJ([strndup])
-  fi
-  gl_STRING_MODULE_INDICATOR([strndup])
-  gl_FUNC_STRNLEN
-  if test $HAVE_DECL_STRNLEN = 0 || test $REPLACE_STRNLEN = 1; then
-    AC_LIBOBJ([strnlen])
-    gl_PREREQ_STRNLEN
-  fi
-  gl_STRING_MODULE_INDICATOR([strnlen])
+  ])
+  gl_STRING_H
+  gl_STRING_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
+  gl_STRINGS_H
+  gl_STRINGS_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
   gl_FUNC_STRSEP
-  if test $HAVE_STRSEP = 0; then
-    AC_LIBOBJ([strsep])
+  gl_CONDITIONAL([GL_COND_OBJ_STRSEP], [test $HAVE_STRSEP = 0])
+  AM_COND_IF([GL_COND_OBJ_STRSEP], [
     gl_PREREQ_STRSEP
-  fi
+  ])
   gl_STRING_MODULE_INDICATOR([strsep])
   gl_FUNC_STRSTR_SIMPLE
   if test $REPLACE_STRSTR = 1; then
     AC_LIBOBJ([strstr])
   fi
   gl_STRING_MODULE_INDICATOR([strstr])
-  gl_HEADER_SYS_SOCKET
+  gl_SYS_SOCKET_H
+  gl_SYS_SOCKET_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
+  gl_SYS_STAT_H
+  gl_SYS_STAT_H_REQUIRE_DEFAULTS
   AC_PROG_MKDIR_P
   gl_SYS_TYPES_H
+  gl_SYS_TYPES_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
+  gl_SYS_UIO_H
+  gl_SYS_UIO_H_REQUIRE_DEFAULTS
   AC_PROG_MKDIR_P
-  gl_HEADER_SYS_UIO
+  AC_REQUIRE([gl_THREADLIB])
+  gl_TIME_H
+  gl_TIME_H_REQUIRE_DEFAULTS
   AC_PROG_MKDIR_P
-  gl_THREADLIB
-  gl_HEADER_TIME_H
   gl_TIME_R
-  if test $HAVE_LOCALTIME_R = 0 || test $REPLACE_LOCALTIME_R = 1; then
-    AC_LIBOBJ([time_r])
+  gl_CONDITIONAL([GL_COND_OBJ_TIME_R],
+                 [test $HAVE_LOCALTIME_R = 0 || test $REPLACE_LOCALTIME_R = 1])
+  AM_COND_IF([GL_COND_OBJ_TIME_R], [
     gl_PREREQ_TIME_R
-  fi
+  ])
   gl_TIME_MODULE_INDICATOR([time_r])
   gl_FUNC_TIMEGM
-  if test $HAVE_TIMEGM = 0 || test $REPLACE_TIMEGM = 1; then
-    AC_LIBOBJ([timegm])
+  gl_CONDITIONAL([GL_COND_OBJ_TIMEGM],
+                 [test $HAVE_TIMEGM = 0 || test $REPLACE_TIMEGM = 1])
+  AM_COND_IF([GL_COND_OBJ_TIMEGM], [
     gl_PREREQ_TIMEGM
-  fi
+  ])
   gl_TIME_MODULE_INDICATOR([timegm])
   gl_UNISTD_H
+  gl_UNISTD_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
+  gl_FUNC_GLIBC_UNLOCKED_IO
   gl_FUNC_UNSETENV
-  if test $HAVE_UNSETENV = 0 || test $REPLACE_UNSETENV = 1; then
-    AC_LIBOBJ([unsetenv])
+  gl_CONDITIONAL([GL_COND_OBJ_UNSETENV],
+                 [test $HAVE_UNSETENV = 0 || test $REPLACE_UNSETENV = 1])
+  AM_COND_IF([GL_COND_OBJ_UNSETENV], [
     gl_PREREQ_UNSETENV
-  fi
+  ])
   gl_STDLIB_MODULE_INDICATOR([unsetenv])
+  AC_C_VARARRAYS
+  AC_REQUIRE([AC_C_RESTRICT])
   gl_FUNC_VASNPRINTF
   gl_FUNC_VASPRINTF
   gl_STDIO_MODULE_INDICATOR([vasprintf])
@@ -475,16 +777,34 @@ AC_DEFUN([gl_INIT],
   gl_FUNC_VSNPRINTF
   gl_STDIO_MODULE_INDICATOR([vsnprintf])
   gl_WCHAR_H
+  gl_WCHAR_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
   gl_FUNC_WCRTOMB
-  if test $HAVE_WCRTOMB = 0 || test $REPLACE_WCRTOMB = 1; then
-    AC_LIBOBJ([wcrtomb])
+  gl_CONDITIONAL([GL_COND_OBJ_WCRTOMB],
+                 [test $HAVE_WCRTOMB = 0 || test $REPLACE_WCRTOMB = 1])
+  AM_COND_IF([GL_COND_OBJ_WCRTOMB], [
     gl_PREREQ_WCRTOMB
-  fi
+  ])
   gl_WCHAR_MODULE_INDICATOR([wcrtomb])
   gl_WCTYPE_H
+  gl_WCTYPE_H_REQUIRE_DEFAULTS
+  AC_PROG_MKDIR_P
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  gl_CONDITIONAL([GL_COND_OBJ_WINDOWS_MUTEX],
+                 [case "$host_os" in mingw*) true;; *) false;; esac])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  gl_CONDITIONAL([GL_COND_OBJ_WINDOWS_ONCE],
+                 [case "$host_os" in mingw*) true;; *) false;; esac])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  gl_CONDITIONAL([GL_COND_OBJ_WINDOWS_RECMUTEX],
+                 [case "$host_os" in mingw*) true;; *) false;; esac])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  gl_CONDITIONAL([GL_COND_OBJ_WINDOWS_RWLOCK],
+                 [case "$host_os" in mingw*) true;; *) false;; esac])
   gl_XALLOC
+  gl_MODULE_INDICATOR([xalloc])
+  gl_MODULE_INDICATOR([xalloc-die])
   gl_XSIZE
-  gl_XSTRNDUP
   # End of code from modules
   m4_ifval(gl_LIBSOURCES_LIST, [
     m4_syscmd([test ! -d ]m4_defn([gl_LIBSOURCES_DIR])[ ||
@@ -497,6 +817,8 @@ AC_DEFUN([gl_INIT],
       m4_if(m4_sysval, [0], [],
         [AC_FATAL([expected source file, required through AC_LIBSOURCES, not found])])
   ])
+  m4_popdef([GL_MODULE_INDICATOR_PREFIX])
+  m4_popdef([GL_MACRO_PREFIX])
   m4_popdef([gl_LIBSOURCES_DIR])
   m4_popdef([gl_LIBSOURCES_LIST])
   m4_popdef([AC_LIBSOURCES])
@@ -505,16 +827,28 @@ AC_DEFUN([gl_INIT],
   AC_CONFIG_COMMANDS_PRE([
     gl_libobjs=
     gl_ltlibobjs=
+    gl_libobjdeps=
     if test -n "$gl_LIBOBJS"; then
       # Remove the extension.
+changequote(,)dnl
       sed_drop_objext='s/\.o$//;s/\.obj$//'
+      sed_dirname1='s,//*,/,g'
+      sed_dirname2='s,\(.\)/$,\1,'
+      sed_dirname3='s,^[^/]*$,.,'
+      sed_dirname4='s,\(.\)/[^/]*$,\1,'
+      sed_basename1='s,.*/,,'
+changequote([, ])dnl
       for i in `for i in $gl_LIBOBJS; do echo "$i"; done | sed -e "$sed_drop_objext" | sort | uniq`; do
         gl_libobjs="$gl_libobjs $i.$ac_objext"
         gl_ltlibobjs="$gl_ltlibobjs $i.lo"
+        i_dir=`echo "$i" | sed -e "$sed_dirname1" -e "$sed_dirname2" -e "$sed_dirname3" -e "$sed_dirname4"`
+        i_base=`echo "$i" | sed -e "$sed_basename1"`
+        gl_libobjdeps="$gl_libobjdeps $i_dir/\$(DEPDIR)/$i_base.Po"
       done
     fi
     AC_SUBST([gl_LIBOBJS], [$gl_libobjs])
     AC_SUBST([gl_LTLIBOBJS], [$gl_ltlibobjs])
+    AC_SUBST([gl_LIBOBJDEPS], [$gl_libobjdeps])
   ])
   gltests_libdeps=
   gltests_ltlibdeps=
@@ -523,8 +857,11 @@ AC_DEFUN([gl_INIT],
   m4_pushdef([AC_LIBSOURCES], m4_defn([gltests_LIBSOURCES]))
   m4_pushdef([gltests_LIBSOURCES_LIST], [])
   m4_pushdef([gltests_LIBSOURCES_DIR], [])
+  m4_pushdef([GL_MACRO_PREFIX], [gltests])
+  m4_pushdef([GL_MODULE_INDICATOR_PREFIX], [GL])
   gl_COMMON
   gl_source_base='tests'
+  gl_source_base_prefix=
 changequote(,)dnl
   gltests_WITNESS=IN_`echo "${PACKAGE-$PACKAGE_TARNAME}" | LC_ALL=C tr abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ | LC_ALL=C sed -e 's/[^A-Z0-9_]/_/g'`_GNULIB_TESTS
 changequote([, ])dnl
@@ -543,6 +880,8 @@ changequote([, ])dnl
       m4_if(m4_sysval, [0], [],
         [AC_FATAL([expected source file, required through AC_LIBSOURCES, not found])])
   ])
+  m4_popdef([GL_MODULE_INDICATOR_PREFIX])
+  m4_popdef([GL_MACRO_PREFIX])
   m4_popdef([gltests_LIBSOURCES_DIR])
   m4_popdef([gltests_LIBSOURCES_LIST])
   m4_popdef([AC_LIBSOURCES])
@@ -551,17 +890,30 @@ changequote([, ])dnl
   AC_CONFIG_COMMANDS_PRE([
     gltests_libobjs=
     gltests_ltlibobjs=
+    gltests_libobjdeps=
     if test -n "$gltests_LIBOBJS"; then
       # Remove the extension.
+changequote(,)dnl
       sed_drop_objext='s/\.o$//;s/\.obj$//'
+      sed_dirname1='s,//*,/,g'
+      sed_dirname2='s,\(.\)/$,\1,'
+      sed_dirname3='s,^[^/]*$,.,'
+      sed_dirname4='s,\(.\)/[^/]*$,\1,'
+      sed_basename1='s,.*/,,'
+changequote([, ])dnl
       for i in `for i in $gltests_LIBOBJS; do echo "$i"; done | sed -e "$sed_drop_objext" | sort | uniq`; do
         gltests_libobjs="$gltests_libobjs $i.$ac_objext"
         gltests_ltlibobjs="$gltests_ltlibobjs $i.lo"
+        i_dir=`echo "$i" | sed -e "$sed_dirname1" -e "$sed_dirname2" -e "$sed_dirname3" -e "$sed_dirname4"`
+        i_base=`echo "$i" | sed -e "$sed_basename1"`
+        gltests_libobjdeps="$gltests_libobjdeps $i_dir/\$(DEPDIR)/$i_base.Po"
       done
     fi
     AC_SUBST([gltests_LIBOBJS], [$gltests_libobjs])
     AC_SUBST([gltests_LTLIBOBJS], [$gltests_ltlibobjs])
+    AC_SUBST([gltests_LIBOBJDEPS], [$gltests_libobjdeps])
   ])
+  AC_REQUIRE([gl_CC_GNULIB_WARNINGS])
   LIBGNU_LIBDEPS="$gl_libdeps"
   AC_SUBST([LIBGNU_LIBDEPS])
   LIBGNU_LTLIBDEPS="$gl_ltlibdeps"
@@ -626,75 +978,130 @@ AC_DEFUN([gltests_LIBSOURCES], [
 # gnulib-tool and may be removed by future gnulib-tool invocations.
 AC_DEFUN([gl_FILE_LIST], [
   build-aux/config.rpath
-  build-aux/snippet/_Noreturn.h
-  build-aux/snippet/arg-nonnull.h
-  build-aux/snippet/c++defs.h
-  build-aux/snippet/warn-on-use.h
+  lib/_Noreturn.h
+  lib/af_alg.c
+  lib/af_alg.h
   lib/alloca.in.h
+  lib/arg-nonnull.h
   lib/arpa_inet.in.h
   lib/asnprintf.c
   lib/asprintf.c
+  lib/assert.in.h
+  lib/attribute.h
   lib/base64.c
   lib/base64.h
   lib/basename-lgpl.c
+  lib/basename-lgpl.h
   lib/basename.c
   lib/btowc.c
-  lib/config.charset
+  lib/byteswap.in.h
+  lib/c++defs.h
+  lib/calloc.c
+  lib/cdefs.h
+  lib/cloexec.c
+  lib/cloexec.h
+  lib/close.c
   lib/dirname-lgpl.c
   lib/dirname.c
   lib/dirname.h
-  lib/dosname.h
+  lib/dup2.c
+  lib/dynarray.h
   lib/errno.in.h
   lib/error.c
   lib/error.h
   lib/exitfail.c
   lib/exitfail.h
+  lib/fcntl.c
+  lib/fcntl.in.h
   lib/fd-hook.c
   lib/fd-hook.h
+  lib/fflush.c
+  lib/filename.h
   lib/float+.h
   lib/float.c
   lib/float.in.h
   lib/floor.c
   lib/floorf.c
+  lib/fopen.c
+  lib/fpurge.c
+  lib/freading.c
+  lib/freading.h
+  lib/free.c
+  lib/fseek.c
+  lib/fseeko.c
+  lib/fstat.c
   lib/fsusage.c
   lib/fsusage.h
-  lib/full-read.c
-  lib/full-read.h
-  lib/full-write.c
+  lib/ftell.c
+  lib/ftello.c
   lib/gai_strerror.c
   lib/getaddrinfo.c
+  lib/getdelim.c
+  lib/getdtablesize.c
   lib/gethostname.c
+  lib/getline.c
   lib/getloadavg.c
+  lib/getopt-cdefs.in.h
+  lib/getopt-core.h
+  lib/getopt-ext.h
+  lib/getopt-pfx-core.h
+  lib/getopt-pfx-ext.h
   lib/getopt.c
   lib/getopt.in.h
   lib/getopt1.c
   lib/getopt_int.h
+  lib/getprogname.c
+  lib/getprogname.h
   lib/gettext.h
+  lib/gl_openssl.h
   lib/glthread/lock.c
   lib/glthread/lock.h
   lib/glthread/threadlib.c
+  lib/hard-locale.c
+  lib/hard-locale.h
+  lib/ialloc.c
+  lib/ialloc.h
   lib/idpriv-droptemp.c
   lib/idpriv.h
+  lib/idx.h
   lib/inet_ntop.c
+  lib/intprops-internal.h
   lib/intprops.h
+  lib/inttypes.in.h
   lib/itold.c
   lib/langinfo.in.h
+  lib/lc-charset-dispatch.c
+  lib/lc-charset-dispatch.h
+  lib/libc-config.h
+  lib/limits.in.h
   lib/localcharset.c
   lib/localcharset.h
   lib/locale.in.h
   lib/localeconv.c
+  lib/lseek.c
   lib/malloc.c
+  lib/malloc/dynarray-skeleton.c
+  lib/malloc/dynarray.h
+  lib/malloc/dynarray_at_failure.c
+  lib/malloc/dynarray_emplace_enlarge.c
+  lib/malloc/dynarray_finalize.c
+  lib/malloc/dynarray_resize.c
+  lib/malloc/dynarray_resize_clear.c
   lib/malloca.c
   lib/malloca.h
-  lib/malloca.valgrind
   lib/math.c
   lib/math.in.h
+  lib/mbrtowc-impl-utf8.h
+  lib/mbrtowc-impl.h
   lib/mbrtowc.c
   lib/mbsinit.c
   lib/mbtowc-impl.h
+  lib/mbtowc-lock.c
+  lib/mbtowc-lock.h
   lib/mbtowc.c
   lib/memchr.c
   lib/memchr.valgrind
+  lib/minmax.h
   lib/mktime-internal.h
   lib/mktime.c
   lib/mountlist.c
@@ -705,33 +1112,45 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/msvc-nothrow.h
   lib/netdb.in.h
   lib/netinet_in.in.h
+  lib/nl_langinfo-lock.c
   lib/nl_langinfo.c
+  lib/open.c
+  lib/pathmax.h
   lib/printf-args.c
   lib/printf-args.h
   lib/printf-parse.c
   lib/printf-parse.h
-  lib/read.c
-  lib/ref-add.sin
-  lib/ref-del.sin
+  lib/realloc.c
+  lib/reallocarray.c
   lib/regcomp.c
   lib/regex.c
   lib/regex.h
   lib/regex_internal.c
   lib/regex_internal.h
   lib/regexec.c
-  lib/safe-read.c
-  lib/safe-read.h
   lib/setenv.c
+  lib/setlocale-lock.c
+  lib/setlocale_null.c
+  lib/setlocale_null.h
+  lib/sha1-stream.c
   lib/sha1.c
   lib/sha1.h
   lib/size_max.h
   lib/snprintf.c
   lib/sockets.c
   lib/sockets.h
+  lib/stat-time.c
+  lib/stat-time.h
+  lib/stat-w32.c
+  lib/stat-w32.h
+  lib/stat.c
   lib/stdalign.in.h
-  lib/stdbool.in.h
+  lib/stdckdint.in.h
   lib/stddef.in.h
   lib/stdint.in.h
+  lib/stdio-impl.h
+  lib/stdio-read.c
+  lib/stdio-write.c
   lib/stdio.in.h
   lib/stdlib.in.h
   lib/str-two-way.h
@@ -745,12 +1164,12 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/strings.in.h
   lib/stripslash.c
   lib/strncasecmp.c
-  lib/strndup.c
-  lib/strnlen.c
   lib/strsep.c
   lib/strstr.c
+  lib/sys-limits.h
   lib/sys_socket.c
   lib/sys_socket.in.h
+  lib/sys_stat.in.h
   lib/sys_types.in.h
   lib/sys_uio.in.h
   lib/time.in.h
@@ -758,6 +1177,7 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/timegm.c
   lib/unistd.c
   lib/unistd.in.h
+  lib/unlocked-io.h
   lib/unsetenv.c
   lib/vasnprintf.c
   lib/vasnprintf.h
@@ -765,27 +1185,43 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/verify.h
   lib/vsnprintf.c
   lib/w32sock.h
+  lib/warn-on-use.h
   lib/wchar.in.h
   lib/wcrtomb.c
   lib/wctype-h.c
   lib/wctype.in.h
+  lib/windows-initguard.h
+  lib/windows-mutex.c
+  lib/windows-mutex.h
+  lib/windows-once.c
+  lib/windows-once.h
+  lib/windows-recmutex.c
+  lib/windows-recmutex.h
+  lib/windows-rwlock.c
+  lib/windows-rwlock.h
   lib/xalloc-die.c
   lib/xalloc-oversized.h
   lib/xalloc.h
   lib/xmalloc.c
   lib/xsize.c
   lib/xsize.h
-  lib/xstrndup.c
-  lib/xstrndup.h
   m4/00gnulib.m4
+  m4/__inline.m4
+  m4/absolute-header.m4
+  m4/af_alg.m4
   m4/alloca.m4
   m4/arpa_inet_h.m4
+  m4/assert_h.m4
   m4/base64.m4
   m4/btowc.m4
+  m4/builtin-expect.m4
+  m4/byteswap.m4
+  m4/c-bool.m4
+  m4/calloc.m4
+  m4/close.m4
   m4/codeset.m4
-  m4/configmake.m4
-  m4/dirname.m4
   m4/double-slash-root.m4
+  m4/dup2.m4
   m4/eealloc.m4
   m4/environ.m4
   m4/errno_h.m4
@@ -794,37 +1230,50 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/extensions.m4
   m4/extern-inline.m4
   m4/fcntl-o.m4
+  m4/fcntl.m4
+  m4/fcntl_h.m4
+  m4/fflush.m4
   m4/float_h.m4
   m4/floorf.m4
+  m4/fopen.m4
+  m4/fpurge.m4
+  m4/freading.m4
+  m4/free.m4
+  m4/fseek.m4
+  m4/fseeko.m4
+  m4/fstat.m4
   m4/fstypename.m4
   m4/fsusage.m4
+  m4/ftell.m4
+  m4/ftello.m4
   m4/getaddrinfo.m4
+  m4/getdelim.m4
+  m4/getdtablesize.m4
   m4/gethostname.m4
+  m4/getline.m4
   m4/getloadavg.m4
   m4/getopt.m4
+  m4/getprogname.m4
   m4/gettext.m4
-  m4/glibc2.m4
-  m4/glibc21.m4
+  m4/gl-openssl.m4
   m4/gnulib-common.m4
+  m4/host-cpu-c-abi.m4
   m4/hostent.m4
   m4/iconv.m4
   m4/idpriv.m4
   m4/include_next.m4
   m4/inet_ntop.m4
-  m4/intdiv0.m4
-  m4/intl.m4
-  m4/intldir.m4
+  m4/intl-thread-locale.m4
   m4/intlmacosx.m4
-  m4/intmax.m4
   m4/intmax_t.m4
-  m4/inttypes-pri.m4
+  m4/inttypes.m4
   m4/inttypes_h.m4
   m4/langinfo_h.m4
   m4/largefile.m4
-  m4/lcmessage.m4
   m4/lib-ld.m4
   m4/lib-link.m4
   m4/lib-prefix.m4
+  m4/limits-h.m4
   m4/localcharset.m4
   m4/locale-fr.m4
   m4/locale-ja.m4
@@ -832,8 +1281,7 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/locale_h.m4
   m4/localeconv.m4
   m4/lock.m4
-  m4/longlong.m4
-  m4/ls-mntd-fs.m4
+  m4/lseek.m4
   m4/malloc.m4
   m4/malloca.m4
   m4/math_h.m4
@@ -842,8 +1290,10 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/mbstate_t.m4
   m4/mbtowc.m4
   m4/memchr.m4
+  m4/minmax.m4
   m4/mktime.m4
   m4/mmap-anon.m4
+  m4/mode_t.m4
   m4/mountlist.m4
   m4/msvc-inval.m4
   m4/msvc-nothrow.m4
@@ -854,16 +1304,21 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/nls.m4
   m4/nocrash.m4
   m4/off_t.m4
-  m4/onceonly.m4
+  m4/open-cloexec.m4
+  m4/open-slash.m4
+  m4/open.m4
+  m4/pathmax.m4
+  m4/pid_t.m4
   m4/po.m4
-  m4/printf-posix.m4
   m4/printf.m4
   m4/progtest.m4
-  m4/read.m4
+  m4/pthread_rwlock_rdlock.m4
+  m4/realloc.m4
+  m4/reallocarray.m4
   m4/regex.m4
-  m4/safe-read.m4
   m4/servent.m4
   m4/setenv.m4
+  m4/setlocale_null.m4
   m4/sha1.m4
   m4/size_max.m4
   m4/snprintf.m4
@@ -872,8 +1327,10 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/socklen.m4
   m4/sockpfaf.m4
   m4/ssize_t.m4
+  m4/stat-time.m4
+  m4/stat.m4
+  m4/std-gnu11.m4
   m4/stdalign.m4
-  m4/stdbool.m4
   m4/stddef_h.m4
   m4/stdint.m4
   m4/stdint_h.m4
@@ -884,19 +1341,20 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/strerror.m4
   m4/string_h.m4
   m4/strings_h.m4
-  m4/strndup.m4
-  m4/strnlen.m4
   m4/strsep.m4
   m4/strstr.m4
   m4/sys_socket_h.m4
+  m4/sys_stat_h.m4
   m4/sys_types_h.m4
   m4/sys_uio_h.m4
   m4/threadlib.m4
   m4/time_h.m4
   m4/time_r.m4
   m4/timegm.m4
-  m4/uintmax_t.m4
+  m4/ungetc.m4
   m4/unistd_h.m4
+  m4/unlocked-io.m4
+  m4/vararrays.m4
   m4/vasnprintf.m4
   m4/vasprintf.m4
   m4/visibility.m4
@@ -909,5 +1367,5 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/wint_t.m4
   m4/xalloc.m4
   m4/xsize.m4
-  m4/xstrndup.m4
+  m4/zzgnulib.m4
 ])
diff --git a/gl/m4/gnulib-tool.m4 b/gl/m4/gnulib-tool.m4
index f3dea1a9..a9dd569b 100644
--- a/gl/m4/gnulib-tool.m4
+++ b/gl/m4/gnulib-tool.m4
@@ -1,5 +1,5 @@
-# gnulib-tool.m4 serial 2
-dnl Copyright (C) 2004-2005, 2009-2013 Free Software Foundation, Inc.
+# gnulib-tool.m4 serial 4
+dnl Copyright (C) 2004-2005, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -44,6 +44,12 @@ AC_DEFUN([gl_LGPL], [])
 dnl Usage: gl_MAKEFILE_NAME([FILENAME])
 AC_DEFUN([gl_MAKEFILE_NAME], [])
 
+dnl Usage: gl_TESTS_MAKEFILE_NAME([FILENAME])
+AC_DEFUN([gl_TESTS_MAKEFILE_NAME], [])
+
+dnl Usage: gl_AUTOMAKE_SUBDIR
+AC_DEFUN([gl_AUTOMAKE_SUBDIR], [])
+
 dnl Usage: gl_LIBTOOL
 AC_DEFUN([gl_LIBTOOL], [])
 
diff --git a/gl/m4/host-cpu-c-abi.m4 b/gl/m4/host-cpu-c-abi.m4
new file mode 100644
index 00000000..134f2283
--- /dev/null
+++ b/gl/m4/host-cpu-c-abi.m4
@@ -0,0 +1,678 @@
+# host-cpu-c-abi.m4 serial 15
+dnl Copyright (C) 2002-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible and Sam Steingold.
+
+dnl Sets the HOST_CPU variable to the canonical name of the CPU.
+dnl Sets the HOST_CPU_C_ABI variable to the canonical name of the CPU with its
+dnl C language ABI (application binary interface).
+dnl Also defines __${HOST_CPU}__ and __${HOST_CPU_C_ABI}__ as C macros in
+dnl config.h.
+dnl
+dnl This canonical name can be used to select a particular assembly language
+dnl source file that will interoperate with C code on the given host.
+dnl
+dnl For example:
+dnl * 'i386' and 'sparc' are different canonical names, because code for i386
+dnl   will not run on SPARC CPUs and vice versa. They have different
+dnl   instruction sets.
+dnl * 'sparc' and 'sparc64' are different canonical names, because code for
+dnl   'sparc' and code for 'sparc64' cannot be linked together: 'sparc' code
+dnl   contains 32-bit instructions, whereas 'sparc64' code contains 64-bit
+dnl   instructions. A process on a SPARC CPU can be in 32-bit mode or in 64-bit
+dnl   mode, but not both.
+dnl * 'mips' and 'mipsn32' are different canonical names, because they use
+dnl   different argument passing and return conventions for C functions, and
+dnl   although the instruction set of 'mips' is a large subset of the
+dnl   instruction set of 'mipsn32'.
+dnl * 'mipsn32' and 'mips64' are different canonical names, because they use
+dnl   different sizes for the C types like 'int' and 'void *', and although
+dnl   the instruction sets of 'mipsn32' and 'mips64' are the same.
+dnl * The same canonical name is used for different endiannesses. You can
+dnl   determine the endianness through preprocessor symbols:
+dnl   - 'arm': test __ARMEL__.
+dnl   - 'mips', 'mipsn32', 'mips64': test _MIPSEB vs. _MIPSEL.
+dnl   - 'powerpc64': test _BIG_ENDIAN vs. _LITTLE_ENDIAN.
+dnl * The same name 'i386' is used for CPUs of type i386, i486, i586
+dnl   (Pentium), AMD K7, Pentium II, Pentium IV, etc., because
+dnl   - Instructions that do not exist on all of these CPUs (cmpxchg,
+dnl     MMX, SSE, SSE2, 3DNow! etc.) are not frequently used. If your
+dnl     assembly language source files use such instructions, you will
+dnl     need to make the distinction.
+dnl   - Speed of execution of the common instruction set is reasonable across
+dnl     the entire family of CPUs. If you have assembly language source files
+dnl     that are optimized for particular CPU types (like GNU gmp has), you
+dnl     will need to make the distinction.
+dnl   See <https://en.wikipedia.org/wiki/X86_instruction_listings>.
+AC_DEFUN([gl_HOST_CPU_C_ABI],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_C_ASM])
+  AC_CACHE_CHECK([host CPU and C ABI], [gl_cv_host_cpu_c_abi],
+    [case "$host_cpu" in
+
+changequote(,)dnl
+       i[34567]86 )
+changequote([,])dnl
+         gl_cv_host_cpu_c_abi=i386
+         ;;
+
+       x86_64 )
+         # On x86_64 systems, the C compiler may be generating code in one of
+         # these ABIs:
+         # - 64-bit instruction set, 64-bit pointers, 64-bit 'long': x86_64.
+         # - 64-bit instruction set, 64-bit pointers, 32-bit 'long': x86_64
+         #   with native Windows (mingw, MSVC).
+         # - 64-bit instruction set, 32-bit pointers, 32-bit 'long': x86_64-x32.
+         # - 32-bit instruction set, 32-bit pointers, 32-bit 'long': i386.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if (defined __x86_64__ || defined __amd64__ \
+                     || defined _M_X64 || defined _M_AMD64)
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [AC_COMPILE_IFELSE(
+              [AC_LANG_SOURCE(
+                 [[#if defined __ILP32__ || defined _ILP32
+                    int ok;
+                   #else
+                    error fail
+                   #endif
+                 ]])],
+              [gl_cv_host_cpu_c_abi=x86_64-x32],
+              [gl_cv_host_cpu_c_abi=x86_64])],
+           [gl_cv_host_cpu_c_abi=i386])
+         ;;
+
+changequote(,)dnl
+       alphaev[4-8] | alphaev56 | alphapca5[67] | alphaev6[78] )
+changequote([,])dnl
+         gl_cv_host_cpu_c_abi=alpha
+         ;;
+
+       arm* | aarch64 )
+         # Assume arm with EABI.
+         # On arm64 systems, the C compiler may be generating code in one of
+         # these ABIs:
+         # - aarch64 instruction set, 64-bit pointers, 64-bit 'long': arm64.
+         # - aarch64 instruction set, 32-bit pointers, 32-bit 'long': arm64-ilp32.
+         # - 32-bit instruction set, 32-bit pointers, 32-bit 'long': arm or armhf.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#ifdef __aarch64__
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [AC_COMPILE_IFELSE(
+              [AC_LANG_SOURCE(
+                [[#if defined __ILP32__ || defined _ILP32
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+              [gl_cv_host_cpu_c_abi=arm64-ilp32],
+              [gl_cv_host_cpu_c_abi=arm64])],
+           [# Don't distinguish little-endian and big-endian arm, since they
+            # don't require different machine code for simple operations and
+            # since the user can distinguish them through the preprocessor
+            # defines __ARMEL__ vs. __ARMEB__.
+            # But distinguish arm which passes floating-point arguments and
+            # return values in integer registers (r0, r1, ...) - this is
+            # gcc -mfloat-abi=soft or gcc -mfloat-abi=softfp - from arm which
+            # passes them in float registers (s0, s1, ...) and double registers
+            # (d0, d1, ...) - this is gcc -mfloat-abi=hard. GCC 4.6 or newer
+            # sets the preprocessor defines __ARM_PCS (for the first case) and
+            # __ARM_PCS_VFP (for the second case), but older GCC does not.
+            echo 'double ddd; void func (double dd) { ddd = dd; }' > conftest.c
+            # Look for a reference to the register d0 in the .s file.
+            AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS $gl_c_asm_opt conftest.c) >/dev/null 2>&1
+            if LC_ALL=C grep 'd0,' conftest.$gl_asmext >/dev/null; then
+              gl_cv_host_cpu_c_abi=armhf
+            else
+              gl_cv_host_cpu_c_abi=arm
+            fi
+            rm -f conftest*
+           ])
+         ;;
+
+       hppa1.0 | hppa1.1 | hppa2.0* | hppa64 )
+         # On hppa, the C compiler may be generating 32-bit code or 64-bit
+         # code. In the latter case, it defines _LP64 and __LP64__.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#ifdef __LP64__
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [gl_cv_host_cpu_c_abi=hppa64],
+           [gl_cv_host_cpu_c_abi=hppa])
+         ;;
+
+       ia64* )
+         # On ia64 on HP-UX, the C compiler may be generating 64-bit code or
+         # 32-bit code. In the latter case, it defines _ILP32.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#ifdef _ILP32
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [gl_cv_host_cpu_c_abi=ia64-ilp32],
+           [gl_cv_host_cpu_c_abi=ia64])
+         ;;
+
+       mips* )
+         # We should also check for (_MIPS_SZPTR == 64), but gcc keeps this
+         # at 32.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if defined _MIPS_SZLONG && (_MIPS_SZLONG == 64)
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [gl_cv_host_cpu_c_abi=mips64],
+           [# In the n32 ABI, _ABIN32 is defined, _ABIO32 is not defined (but
+            # may later get defined by <sgidefs.h>), and _MIPS_SIM == _ABIN32.
+            # In the 32 ABI, _ABIO32 is defined, _ABIN32 is not defined (but
+            # may later get defined by <sgidefs.h>), and _MIPS_SIM == _ABIO32.
+            AC_COMPILE_IFELSE(
+              [AC_LANG_SOURCE(
+                 [[#if (_MIPS_SIM == _ABIN32)
+                    int ok;
+                   #else
+                    error fail
+                   #endif
+                 ]])],
+              [gl_cv_host_cpu_c_abi=mipsn32],
+              [gl_cv_host_cpu_c_abi=mips])])
+         ;;
+
+       powerpc* )
+         # Different ABIs are in use on AIX vs. Mac OS X vs. Linux,*BSD.
+         # No need to distinguish them here; the caller may distinguish
+         # them based on the OS.
+         # On powerpc64 systems, the C compiler may still be generating
+         # 32-bit code. And on powerpc-ibm-aix systems, the C compiler may
+         # be generating 64-bit code.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if defined __powerpc64__ || defined __LP64__
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [# On powerpc64, there are two ABIs on Linux: The AIX compatible
+            # one and the ELFv2 one. The latter defines _CALL_ELF=2.
+            AC_COMPILE_IFELSE(
+              [AC_LANG_SOURCE(
+                 [[#if defined _CALL_ELF && _CALL_ELF == 2
+                    int ok;
+                   #else
+                    error fail
+                   #endif
+                 ]])],
+              [gl_cv_host_cpu_c_abi=powerpc64-elfv2],
+              [gl_cv_host_cpu_c_abi=powerpc64])
+           ],
+           [gl_cv_host_cpu_c_abi=powerpc])
+         ;;
+
+       rs6000 )
+         gl_cv_host_cpu_c_abi=powerpc
+         ;;
+
+       riscv32 | riscv64 )
+         # There are 2 architectures (with variants): rv32* and rv64*.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if __riscv_xlen == 64
+                  int ok;
+                #else
+                  error fail
+                #endif
+              ]])],
+           [cpu=riscv64],
+           [cpu=riscv32])
+         # There are 6 ABIs: ilp32, ilp32f, ilp32d, lp64, lp64f, lp64d.
+         # Size of 'long' and 'void *':
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if defined __LP64__
+                  int ok;
+                #else
+                  error fail
+                #endif
+              ]])],
+           [main_abi=lp64],
+           [main_abi=ilp32])
+         # Float ABIs:
+         # __riscv_float_abi_double:
+         #   'float' and 'double' are passed in floating-point registers.
+         # __riscv_float_abi_single:
+         #   'float' are passed in floating-point registers.
+         # __riscv_float_abi_soft:
+         #   No values are passed in floating-point registers.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if defined __riscv_float_abi_double
+                  int ok;
+                #else
+                  error fail
+                #endif
+              ]])],
+           [float_abi=d],
+           [AC_COMPILE_IFELSE(
+              [AC_LANG_SOURCE(
+                 [[#if defined __riscv_float_abi_single
+                     int ok;
+                   #else
+                     error fail
+                   #endif
+                 ]])],
+              [float_abi=f],
+              [float_abi=''])
+           ])
+         gl_cv_host_cpu_c_abi="${cpu}-${main_abi}${float_abi}"
+         ;;
+
+       s390* )
+         # On s390x, the C compiler may be generating 64-bit (= s390x) code
+         # or 31-bit (= s390) code.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if defined __LP64__ || defined __s390x__
+                  int ok;
+                #else
+                  error fail
+                #endif
+              ]])],
+           [gl_cv_host_cpu_c_abi=s390x],
+           [gl_cv_host_cpu_c_abi=s390])
+         ;;
+
+       sparc | sparc64 )
+         # UltraSPARCs running Linux have `uname -m` = "sparc64", but the
+         # C compiler still generates 32-bit code.
+         AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE(
+              [[#if defined __sparcv9 || defined __arch64__
+                 int ok;
+                #else
+                 error fail
+                #endif
+              ]])],
+           [gl_cv_host_cpu_c_abi=sparc64],
+           [gl_cv_host_cpu_c_abi=sparc])
+         ;;
+
+       *)
+         gl_cv_host_cpu_c_abi="$host_cpu"
+         ;;
+     esac
+    ])
+
+  dnl In most cases, $HOST_CPU and $HOST_CPU_C_ABI are the same.
+  HOST_CPU=`echo "$gl_cv_host_cpu_c_abi" | sed -e 's/-.*//'`
+  HOST_CPU_C_ABI="$gl_cv_host_cpu_c_abi"
+  AC_SUBST([HOST_CPU])
+  AC_SUBST([HOST_CPU_C_ABI])
+
+  # This was
+  #   AC_DEFINE_UNQUOTED([__${HOST_CPU}__])
+  #   AC_DEFINE_UNQUOTED([__${HOST_CPU_C_ABI}__])
+  # earlier, but KAI C++ 3.2d doesn't like this.
+  sed -e 's/-/_/g' >> confdefs.h <<EOF
+#ifndef __${HOST_CPU}__
+#define __${HOST_CPU}__ 1
+#endif
+#ifndef __${HOST_CPU_C_ABI}__
+#define __${HOST_CPU_C_ABI}__ 1
+#endif
+EOF
+  AH_TOP([/* CPU and C ABI indicator */
+#ifndef __i386__
+#undef __i386__
+#endif
+#ifndef __x86_64_x32__
+#undef __x86_64_x32__
+#endif
+#ifndef __x86_64__
+#undef __x86_64__
+#endif
+#ifndef __alpha__
+#undef __alpha__
+#endif
+#ifndef __arm__
+#undef __arm__
+#endif
+#ifndef __armhf__
+#undef __armhf__
+#endif
+#ifndef __arm64_ilp32__
+#undef __arm64_ilp32__
+#endif
+#ifndef __arm64__
+#undef __arm64__
+#endif
+#ifndef __hppa__
+#undef __hppa__
+#endif
+#ifndef __hppa64__
+#undef __hppa64__
+#endif
+#ifndef __ia64_ilp32__
+#undef __ia64_ilp32__
+#endif
+#ifndef __ia64__
+#undef __ia64__
+#endif
+#ifndef __loongarch64__
+#undef __loongarch64__
+#endif
+#ifndef __m68k__
+#undef __m68k__
+#endif
+#ifndef __mips__
+#undef __mips__
+#endif
+#ifndef __mipsn32__
+#undef __mipsn32__
+#endif
+#ifndef __mips64__
+#undef __mips64__
+#endif
+#ifndef __powerpc__
+#undef __powerpc__
+#endif
+#ifndef __powerpc64__
+#undef __powerpc64__
+#endif
+#ifndef __powerpc64_elfv2__
+#undef __powerpc64_elfv2__
+#endif
+#ifndef __riscv32__
+#undef __riscv32__
+#endif
+#ifndef __riscv64__
+#undef __riscv64__
+#endif
+#ifndef __riscv32_ilp32__
+#undef __riscv32_ilp32__
+#endif
+#ifndef __riscv32_ilp32f__
+#undef __riscv32_ilp32f__
+#endif
+#ifndef __riscv32_ilp32d__
+#undef __riscv32_ilp32d__
+#endif
+#ifndef __riscv64_ilp32__
+#undef __riscv64_ilp32__
+#endif
+#ifndef __riscv64_ilp32f__
+#undef __riscv64_ilp32f__
+#endif
+#ifndef __riscv64_ilp32d__
+#undef __riscv64_ilp32d__
+#endif
+#ifndef __riscv64_lp64__
+#undef __riscv64_lp64__
+#endif
+#ifndef __riscv64_lp64f__
+#undef __riscv64_lp64f__
+#endif
+#ifndef __riscv64_lp64d__
+#undef __riscv64_lp64d__
+#endif
+#ifndef __s390__
+#undef __s390__
+#endif
+#ifndef __s390x__
+#undef __s390x__
+#endif
+#ifndef __sh__
+#undef __sh__
+#endif
+#ifndef __sparc__
+#undef __sparc__
+#endif
+#ifndef __sparc64__
+#undef __sparc64__
+#endif
+])
+
+])
+
+
+dnl Sets the HOST_CPU_C_ABI_32BIT variable to 'yes' if the C language ABI
+dnl (application binary interface) is a 32-bit one, to 'no' if it is a 64-bit
+dnl one, or to 'unknown' if unknown.
+dnl This is a simplified variant of gl_HOST_CPU_C_ABI.
+AC_DEFUN([gl_HOST_CPU_C_ABI_32BIT],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CACHE_CHECK([32-bit host C ABI], [gl_cv_host_cpu_c_abi_32bit],
+    [if test -n "$gl_cv_host_cpu_c_abi"; then
+       case "$gl_cv_host_cpu_c_abi" in
+         i386 | x86_64-x32 | arm | armhf | arm64-ilp32 | hppa | ia64-ilp32 | mips | mipsn32 | powerpc | riscv*-ilp32* | s390 | sparc)
+           gl_cv_host_cpu_c_abi_32bit=yes ;;
+         x86_64 | alpha | arm64 | hppa64 | ia64 | mips64 | powerpc64 | powerpc64-elfv2 | riscv*-lp64* | s390x | sparc64 )
+           gl_cv_host_cpu_c_abi_32bit=no ;;
+         *)
+           gl_cv_host_cpu_c_abi_32bit=unknown ;;
+       esac
+     else
+       case "$host_cpu" in
+
+         # CPUs that only support a 32-bit ABI.
+         arc \
+         | bfin \
+         | cris* \
+         | csky \
+         | epiphany \
+         | ft32 \
+         | h8300 \
+         | m68k \
+         | microblaze | microblazeel \
+         | nds32 | nds32le | nds32be \
+         | nios2 | nios2eb | nios2el \
+         | or1k* \
+         | or32 \
+         | sh | sh[1234] | sh[1234]e[lb] \
+         | tic6x \
+         | xtensa* )
+           gl_cv_host_cpu_c_abi_32bit=yes
+           ;;
+
+         # CPUs that only support a 64-bit ABI.
+changequote(,)dnl
+         alpha | alphaev[4-8] | alphaev56 | alphapca5[67] | alphaev6[78] \
+         | mmix )
+changequote([,])dnl
+           gl_cv_host_cpu_c_abi_32bit=no
+           ;;
+
+changequote(,)dnl
+         i[34567]86 )
+changequote([,])dnl
+           gl_cv_host_cpu_c_abi_32bit=yes
+           ;;
+
+         x86_64 )
+           # On x86_64 systems, the C compiler may be generating code in one of
+           # these ABIs:
+           # - 64-bit instruction set, 64-bit pointers, 64-bit 'long': x86_64.
+           # - 64-bit instruction set, 64-bit pointers, 32-bit 'long': x86_64
+           #   with native Windows (mingw, MSVC).
+           # - 64-bit instruction set, 32-bit pointers, 32-bit 'long': x86_64-x32.
+           # - 32-bit instruction set, 32-bit pointers, 32-bit 'long': i386.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if (defined __x86_64__ || defined __amd64__ \
+                       || defined _M_X64 || defined _M_AMD64) \
+                      && !(defined __ILP32__ || defined _ILP32)
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         arm* | aarch64 )
+           # Assume arm with EABI.
+           # On arm64 systems, the C compiler may be generating code in one of
+           # these ABIs:
+           # - aarch64 instruction set, 64-bit pointers, 64-bit 'long': arm64.
+           # - aarch64 instruction set, 32-bit pointers, 32-bit 'long': arm64-ilp32.
+           # - 32-bit instruction set, 32-bit pointers, 32-bit 'long': arm or armhf.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if defined __aarch64__ && !(defined __ILP32__ || defined _ILP32)
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         hppa1.0 | hppa1.1 | hppa2.0* | hppa64 )
+           # On hppa, the C compiler may be generating 32-bit code or 64-bit
+           # code. In the latter case, it defines _LP64 and __LP64__.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#ifdef __LP64__
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         ia64* )
+           # On ia64 on HP-UX, the C compiler may be generating 64-bit code or
+           # 32-bit code. In the latter case, it defines _ILP32.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#ifdef _ILP32
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=yes],
+             [gl_cv_host_cpu_c_abi_32bit=no])
+           ;;
+
+         mips* )
+           # We should also check for (_MIPS_SZPTR == 64), but gcc keeps this
+           # at 32.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if defined _MIPS_SZLONG && (_MIPS_SZLONG == 64)
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         powerpc* )
+           # Different ABIs are in use on AIX vs. Mac OS X vs. Linux,*BSD.
+           # No need to distinguish them here; the caller may distinguish
+           # them based on the OS.
+           # On powerpc64 systems, the C compiler may still be generating
+           # 32-bit code. And on powerpc-ibm-aix systems, the C compiler may
+           # be generating 64-bit code.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if defined __powerpc64__ || defined __LP64__
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         rs6000 )
+           gl_cv_host_cpu_c_abi_32bit=yes
+           ;;
+
+         riscv32 | riscv64 )
+           # There are 6 ABIs: ilp32, ilp32f, ilp32d, lp64, lp64f, lp64d.
+           # Size of 'long' and 'void *':
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if defined __LP64__
+                    int ok;
+                  #else
+                    error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         s390* )
+           # On s390x, the C compiler may be generating 64-bit (= s390x) code
+           # or 31-bit (= s390) code.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if defined __LP64__ || defined __s390x__
+                    int ok;
+                  #else
+                    error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         sparc | sparc64 )
+           # UltraSPARCs running Linux have `uname -m` = "sparc64", but the
+           # C compiler still generates 32-bit code.
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE(
+                [[#if defined __sparcv9 || defined __arch64__
+                   int ok;
+                  #else
+                   error fail
+                  #endif
+                ]])],
+             [gl_cv_host_cpu_c_abi_32bit=no],
+             [gl_cv_host_cpu_c_abi_32bit=yes])
+           ;;
+
+         *)
+           gl_cv_host_cpu_c_abi_32bit=unknown
+           ;;
+       esac
+     fi
+    ])
+
+  HOST_CPU_C_ABI_32BIT="$gl_cv_host_cpu_c_abi_32bit"
+])
diff --git a/gl/m4/hostent.m4 b/gl/m4/hostent.m4
index 72be876b..3b2cc2b2 100644
--- a/gl/m4/hostent.m4
+++ b/gl/m4/hostent.m4
@@ -1,5 +1,5 @@
-# hostent.m4 serial 2
-dnl Copyright (C) 2008, 2010-2013 Free Software Foundation, Inc.
+# hostent.m4 serial 4
+dnl Copyright (C) 2008, 2010-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -8,12 +8,12 @@ AC_DEFUN([gl_HOSTENT],
 [
   dnl Where are gethostent(), sethostent(), endhostent(), gethostbyname(),
   dnl gethostbyaddr() defined?
-  dnl - On Solaris, they are in libnsl. Ignore libxnet.
+  dnl - On Solaris < 11.4, they are in libnsl. Ignore libxnet.
   dnl - On Haiku, they are in libnetwork.
   dnl - On BeOS, they are in libnet.
   dnl - On native Windows, they are in ws2_32.dll.
   dnl - Otherwise they are in libc.
-  AC_REQUIRE([gl_HEADER_SYS_SOCKET])dnl for HAVE_SYS_SOCKET_H, HAVE_WINSOCK2_H
+  AC_REQUIRE([gl_SYS_SOCKET_H])dnl for HAVE_SYS_SOCKET_H, HAVE_WINSOCK2_H
   HOSTENT_LIB=
   gl_saved_libs="$LIBS"
   AC_SEARCH_LIBS([gethostbyname], [nsl network net],
diff --git a/gl/m4/iconv.m4 b/gl/m4/iconv.m4
index a5036465..ff5d5261 100644
--- a/gl/m4/iconv.m4
+++ b/gl/m4/iconv.m4
@@ -1,11 +1,18 @@
-# iconv.m4 serial 18 (gettext-0.18.2)
-dnl Copyright (C) 2000-2002, 2007-2013 Free Software Foundation, Inc.
+# iconv.m4 serial 26
+dnl Copyright (C) 2000-2002, 2007-2014, 2016-2023 Free Software Foundation,
+dnl Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl From Bruno Haible.
 
+AC_PREREQ([2.64])
+
+dnl Note: AM_ICONV is documented in the GNU gettext manual
+dnl <https://www.gnu.org/software/gettext/manual/html_node/AM_005fICONV.html>.
+dnl Don't make changes that are incompatible with that documentation!
+
 AC_DEFUN([AM_ICONV_LINKFLAGS_BODY],
 [
   dnl Prerequisites of AC_LIB_LINKFLAGS_BODY.
@@ -72,27 +79,34 @@ AC_DEFUN([AM_ICONV_LINK],
       if test $am_cv_lib_iconv = yes; then
         LIBS="$LIBS $LIBICONV"
       fi
-      AC_RUN_IFELSE(
-        [AC_LANG_SOURCE([[
+      am_cv_func_iconv_works=no
+      for ac_iconv_const in '' 'const'; do
+        AC_RUN_IFELSE(
+          [AC_LANG_PROGRAM(
+             [[
 #include <iconv.h>
 #include <string.h>
-int main ()
-{
-  int result = 0;
-  /* Test against AIX 5.1 bug: Failures are not distinguishable from successful
-     returns.  */
+
+#ifndef ICONV_CONST
+# define ICONV_CONST $ac_iconv_const
+#endif
+             ]],
+             [[int result = 0;
+  /* Test against AIX 5.1...7.2 bug: Failures are not distinguishable from
+     successful returns.  This is even documented in
+     <https://www.ibm.com/support/knowledgecenter/ssw_aix_72/i_bostechref/iconv.html> */
   {
     iconv_t cd_utf8_to_88591 = iconv_open ("ISO8859-1", "UTF-8");
     if (cd_utf8_to_88591 != (iconv_t)(-1))
       {
-        static const char input[] = "\342\202\254"; /* EURO SIGN */
+        static ICONV_CONST char input[] = "\342\202\254"; /* EURO SIGN */
         char buf[10];
-        const char *inptr = input;
+        ICONV_CONST char *inptr = input;
         size_t inbytesleft = strlen (input);
         char *outptr = buf;
         size_t outbytesleft = sizeof (buf);
         size_t res = iconv (cd_utf8_to_88591,
-                            (char **) &inptr, &inbytesleft,
+                            &inptr, &inbytesleft,
                             &outptr, &outbytesleft);
         if (res == 0)
           result |= 1;
@@ -105,14 +119,14 @@ int main ()
     iconv_t cd_ascii_to_88591 = iconv_open ("ISO8859-1", "646");
     if (cd_ascii_to_88591 != (iconv_t)(-1))
       {
-        static const char input[] = "\263";
+        static ICONV_CONST char input[] = "\263";
         char buf[10];
-        const char *inptr = input;
+        ICONV_CONST char *inptr = input;
         size_t inbytesleft = strlen (input);
         char *outptr = buf;
         size_t outbytesleft = sizeof (buf);
         size_t res = iconv (cd_ascii_to_88591,
-                            (char **) &inptr, &inbytesleft,
+                            &inptr, &inbytesleft,
                             &outptr, &outbytesleft);
         if (res == 0)
           result |= 2;
@@ -124,14 +138,14 @@ int main ()
     iconv_t cd_88591_to_utf8 = iconv_open ("UTF-8", "ISO-8859-1");
     if (cd_88591_to_utf8 != (iconv_t)(-1))
       {
-        static const char input[] = "\304";
+        static ICONV_CONST char input[] = "\304";
         static char buf[2] = { (char)0xDE, (char)0xAD };
-        const char *inptr = input;
+        ICONV_CONST char *inptr = input;
         size_t inbytesleft = 1;
         char *outptr = buf;
         size_t outbytesleft = 1;
         size_t res = iconv (cd_88591_to_utf8,
-                            (char **) &inptr, &inbytesleft,
+                            &inptr, &inbytesleft,
                             &outptr, &outbytesleft);
         if (res != (size_t)(-1) || outptr - buf > 1 || buf[1] != (char)0xAD)
           result |= 4;
@@ -144,14 +158,14 @@ int main ()
     iconv_t cd_88591_to_utf8 = iconv_open ("utf8", "iso88591");
     if (cd_88591_to_utf8 != (iconv_t)(-1))
       {
-        static const char input[] = "\304rger mit b\366sen B\374bchen ohne Augenma\337";
+        static ICONV_CONST char input[] = "\304rger mit b\366sen B\374bchen ohne Augenma\337";
         char buf[50];
-        const char *inptr = input;
+        ICONV_CONST char *inptr = input;
         size_t inbytesleft = strlen (input);
         char *outptr = buf;
         size_t outbytesleft = sizeof (buf);
         size_t res = iconv (cd_88591_to_utf8,
-                            (char **) &inptr, &inbytesleft,
+                            &inptr, &inbytesleft,
                             &outptr, &outbytesleft);
         if ((int)res > 0)
           result |= 8;
@@ -161,27 +175,36 @@ int main ()
 #endif
   /* Test against HP-UX 11.11 bug: No converter from EUC-JP to UTF-8 is
      provided.  */
-  if (/* Try standardized names.  */
-      iconv_open ("UTF-8", "EUC-JP") == (iconv_t)(-1)
-      /* Try IRIX, OSF/1 names.  */
-      && iconv_open ("UTF-8", "eucJP") == (iconv_t)(-1)
-      /* Try AIX names.  */
-      && iconv_open ("UTF-8", "IBM-eucJP") == (iconv_t)(-1)
-      /* Try HP-UX names.  */
-      && iconv_open ("utf8", "eucJP") == (iconv_t)(-1))
-    result |= 16;
+  {
+    /* Try standardized names.  */
+    iconv_t cd1 = iconv_open ("UTF-8", "EUC-JP");
+    /* Try IRIX, OSF/1 names.  */
+    iconv_t cd2 = iconv_open ("UTF-8", "eucJP");
+    /* Try AIX names.  */
+    iconv_t cd3 = iconv_open ("UTF-8", "IBM-eucJP");
+    /* Try HP-UX names.  */
+    iconv_t cd4 = iconv_open ("utf8", "eucJP");
+    if (cd1 == (iconv_t)(-1) && cd2 == (iconv_t)(-1)
+        && cd3 == (iconv_t)(-1) && cd4 == (iconv_t)(-1))
+      result |= 16;
+    if (cd1 != (iconv_t)(-1))
+      iconv_close (cd1);
+    if (cd2 != (iconv_t)(-1))
+      iconv_close (cd2);
+    if (cd3 != (iconv_t)(-1))
+      iconv_close (cd3);
+    if (cd4 != (iconv_t)(-1))
+      iconv_close (cd4);
+  }
   return result;
-}]])],
-        [am_cv_func_iconv_works=yes],
-        [am_cv_func_iconv_works=no],
-        [
-changequote(,)dnl
-         case "$host_os" in
-           aix* | hpux*) am_cv_func_iconv_works="guessing no" ;;
-           *)            am_cv_func_iconv_works="guessing yes" ;;
-         esac
-changequote([,])dnl
-        ])
+]])],
+          [am_cv_func_iconv_works=yes], ,
+          [case "$host_os" in
+             aix* | hpux*) am_cv_func_iconv_works="guessing no" ;;
+             *)            am_cv_func_iconv_works="guessing yes" ;;
+           esac])
+        test "$am_cv_func_iconv_works" = no || break
+      done
       LIBS="$am_save_LIBS"
     ])
     case "$am_cv_func_iconv_works" in
@@ -209,60 +232,62 @@ changequote([,])dnl
   AC_SUBST([LTLIBICONV])
 ])
 
-dnl Define AM_ICONV using AC_DEFUN_ONCE for Autoconf >= 2.64, in order to
-dnl avoid warnings like
+dnl Define AM_ICONV using AC_DEFUN_ONCE, in order to avoid warnings like
 dnl "warning: AC_REQUIRE: `AM_ICONV' was expanded before it was required".
-dnl This is tricky because of the way 'aclocal' is implemented:
-dnl - It requires defining an auxiliary macro whose name ends in AC_DEFUN.
-dnl   Otherwise aclocal's initial scan pass would miss the macro definition.
-dnl - It requires a line break inside the AC_DEFUN_ONCE and AC_DEFUN expansions.
-dnl   Otherwise aclocal would emit many "Use of uninitialized value $1"
-dnl   warnings.
-m4_define([gl_iconv_AC_DEFUN],
-  m4_version_prereq([2.64],
-    [[AC_DEFUN_ONCE(
-        [$1], [$2])]],
-    [m4_ifdef([gl_00GNULIB],
-       [[AC_DEFUN_ONCE(
-           [$1], [$2])]],
-       [[AC_DEFUN(
-           [$1], [$2])]])]))
-gl_iconv_AC_DEFUN([AM_ICONV],
+AC_DEFUN_ONCE([AM_ICONV],
 [
   AM_ICONV_LINK
   if test "$am_cv_func_iconv" = yes; then
-    AC_MSG_CHECKING([for iconv declaration])
-    AC_CACHE_VAL([am_cv_proto_iconv], [
-      AC_COMPILE_IFELSE(
-        [AC_LANG_PROGRAM(
-           [[
+    AC_CACHE_CHECK([whether iconv is compatible with its POSIX signature],
+      [gl_cv_iconv_nonconst],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[
 #include <stdlib.h>
 #include <iconv.h>
 extern
 #ifdef __cplusplus
 "C"
 #endif
-#if defined(__STDC__) || defined(_MSC_VER) || defined(__cplusplus)
 size_t iconv (iconv_t cd, char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);
-#else
-size_t iconv();
-#endif
-           ]],
-           [[]])],
-        [am_cv_proto_iconv_arg1=""],
-        [am_cv_proto_iconv_arg1="const"])
-      am_cv_proto_iconv="extern size_t iconv (iconv_t cd, $am_cv_proto_iconv_arg1 char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);"])
-    am_cv_proto_iconv=`echo "[$]am_cv_proto_iconv" | tr -s ' ' | sed -e 's/( /(/'`
-    AC_MSG_RESULT([
-         $am_cv_proto_iconv])
-    AC_DEFINE_UNQUOTED([ICONV_CONST], [$am_cv_proto_iconv_arg1],
-      [Define as const if the declaration of iconv() needs const.])
-    dnl Also substitute ICONV_CONST in the gnulib generated <iconv.h>.
-    m4_ifdef([gl_ICONV_H_DEFAULTS],
-      [AC_REQUIRE([gl_ICONV_H_DEFAULTS])
-       if test -n "$am_cv_proto_iconv_arg1"; then
-         ICONV_CONST="const"
-       fi
+            ]],
+            [[]])],
+         [gl_cv_iconv_nonconst=yes],
+         [gl_cv_iconv_nonconst=no])
       ])
+  else
+    dnl When compiling GNU libiconv on a system that does not have iconv yet,
+    dnl pick the POSIX compliant declaration without 'const'.
+    gl_cv_iconv_nonconst=yes
+  fi
+  if test $gl_cv_iconv_nonconst = yes; then
+    iconv_arg1=""
+  else
+    iconv_arg1="const"
+  fi
+  AC_DEFINE_UNQUOTED([ICONV_CONST], [$iconv_arg1],
+    [Define as const if the declaration of iconv() needs const.])
+  dnl Also substitute ICONV_CONST in the gnulib generated <iconv.h>.
+  m4_ifdef([gl_ICONV_H_DEFAULTS],
+    [AC_REQUIRE([gl_ICONV_H_DEFAULTS])
+     if test $gl_cv_iconv_nonconst != yes; then
+       ICONV_CONST="const"
+     fi
+    ])
+
+  dnl A summary result, for those packages which want to print a summary at the
+  dnl end of the configuration.
+  if test "$am_func_iconv" = yes; then
+    if test -n "$LIBICONV"; then
+      am_cv_func_iconv_summary='yes, in libiconv'
+    else
+      am_cv_func_iconv_summary='yes, in libc'
+    fi
+  else
+    if test "$am_cv_func_iconv" = yes; then
+      am_cv_func_iconv_summary='not working, consider installing GNU libiconv'
+    else
+      am_cv_func_iconv_summary='no, consider installing GNU libiconv'
+    fi
   fi
 ])
diff --git a/gl/m4/idpriv.m4 b/gl/m4/idpriv.m4
index 167f5238..fc3dd17d 100644
--- a/gl/m4/idpriv.m4
+++ b/gl/m4/idpriv.m4
@@ -1,5 +1,5 @@
 # idpriv.m4 serial 1
-dnl Copyright (C) 2009-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/include_next.m4 b/gl/m4/include_next.m4
index 108d9456..9f19215e 100644
--- a/gl/m4/include_next.m4
+++ b/gl/m4/include_next.m4
@@ -1,12 +1,13 @@
-# include_next.m4 serial 23
-dnl Copyright (C) 2006-2013 Free Software Foundation, Inc.
+# include_next.m4 serial 26
+dnl Copyright (C) 2006-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl From Paul Eggert and Derek Price.
 
-dnl Sets INCLUDE_NEXT and PRAGMA_SYSTEM_HEADER.
+dnl Sets INCLUDE_NEXT, INCLUDE_NEXT_AS_FIRST_DIRECTIVE, PRAGMA_SYSTEM_HEADER,
+dnl and PRAGMA_COLUMNS.
 dnl
 dnl INCLUDE_NEXT expands to 'include_next' if the compiler supports it, or to
 dnl 'include' otherwise.
@@ -105,19 +106,21 @@ dnl We intentionally avoid using AC_LANG_SOURCE here.
   AC_SUBST([INCLUDE_NEXT])
   AC_SUBST([INCLUDE_NEXT_AS_FIRST_DIRECTIVE])
   AC_SUBST([PRAGMA_SYSTEM_HEADER])
-  AC_CACHE_CHECK([whether system header files limit the line length],
-    [gl_cv_pragma_columns],
-    [dnl HP NonStop systems, which define __TANDEM, have this misfeature.
-     AC_EGREP_CPP([choke me],
+
+  dnl HP NonStop systems, which define __TANDEM, limit the line length
+  dnl after including some system header files.
+  AC_CACHE_CHECK([whether source code line length is unlimited],
+    [gl_cv_source_line_length_unlimited],
+    [AC_EGREP_CPP([choke me],
        [
 #ifdef __TANDEM
 choke me
 #endif
        ],
-       [gl_cv_pragma_columns=yes],
-       [gl_cv_pragma_columns=no])
+       [gl_cv_source_line_length_unlimited=no],
+       [gl_cv_source_line_length_unlimited=yes])
     ])
-  if test $gl_cv_pragma_columns = yes; then
+  if test $gl_cv_source_line_length_unlimited = no; then
     PRAGMA_COLUMNS="#pragma COLUMNS 10000"
   else
     PRAGMA_COLUMNS=
@@ -175,89 +178,40 @@ AC_DEFUN([gl_NEXT_HEADERS_INTERNAL],
     [AC_CHECK_HEADERS_ONCE([$1])
     ])
 
-dnl FIXME: gl_next_header and gl_header_exists must be used unquoted
-dnl until we can assume autoconf 2.64 or newer.
   m4_foreach_w([gl_HEADER_NAME], [$1],
     [AS_VAR_PUSHDEF([gl_next_header],
                     [gl_cv_next_]m4_defn([gl_HEADER_NAME]))
      if test $gl_cv_have_include_next = yes; then
-       AS_VAR_SET(gl_next_header, ['<'gl_HEADER_NAME'>'])
+       AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
      else
        AC_CACHE_CHECK(
          [absolute name of <]m4_defn([gl_HEADER_NAME])[>],
-         m4_defn([gl_next_header]),
+         [gl_next_header],
          [m4_if([$2], [check],
             [AS_VAR_PUSHDEF([gl_header_exists],
                             [ac_cv_header_]m4_defn([gl_HEADER_NAME]))
-             if test AS_VAR_GET(gl_header_exists) = yes; then
+             if test AS_VAR_GET([gl_header_exists]) = yes; then
              AS_VAR_POPDEF([gl_header_exists])
             ])
-               AC_LANG_CONFTEST(
-                 [AC_LANG_SOURCE(
-                    [[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]]
-                  )])
-               dnl AIX "xlc -E" and "cc -E" omit #line directives for header
-               dnl files that contain only a #include of other header files and
-               dnl no non-comment tokens of their own. This leads to a failure
-               dnl to detect the absolute name of <dirent.h>, <signal.h>,
-               dnl <poll.h> and others. The workaround is to force preservation
-               dnl of comments through option -C. This ensures all necessary
-               dnl #line directives are present. GCC supports option -C as well.
-               case "$host_os" in
-                 aix*) gl_absname_cpp="$ac_cpp -C" ;;
-                 *)    gl_absname_cpp="$ac_cpp" ;;
-               esac
-changequote(,)
-               case "$host_os" in
-                 mingw*)
-                   dnl For the sake of native Windows compilers (excluding gcc),
-                   dnl treat backslash as a directory separator, like /.
-                   dnl Actually, these compilers use a double-backslash as
-                   dnl directory separator, inside the
-                   dnl   # line "filename"
-                   dnl directives.
-                   gl_dirsep_regex='[/\\]'
-                   ;;
-                 *)
-                   gl_dirsep_regex='\/'
-                   ;;
-               esac
-               dnl A sed expression that turns a string into a basic regular
-               dnl expression, for use within "/.../".
-               gl_make_literal_regex_sed='s,[]$^\\.*/[],\\&,g'
-changequote([,])
-               gl_header_literal_regex=`echo ']m4_defn([gl_HEADER_NAME])[' \
-                                        | sed -e "$gl_make_literal_regex_sed"`
-               gl_absolute_header_sed="/${gl_dirsep_regex}${gl_header_literal_regex}/"'{
-                   s/.*"\(.*'"${gl_dirsep_regex}${gl_header_literal_regex}"'\)".*/\1/
-changequote(,)dnl
-                   s|^/[^/]|//&|
-changequote([,])dnl
-                   p
-                   q
-                 }'
-               dnl eval is necessary to expand gl_absname_cpp.
-               dnl Ultrix and Pyramid sh refuse to redirect output of eval,
-               dnl so use subshell.
-               AS_VAR_SET(gl_next_header,
-                 ['"'`(eval "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
-                      sed -n "$gl_absolute_header_sed"`'"'])
+          gl_ABSOLUTE_HEADER_ONE(gl_HEADER_NAME)
+          AS_VAR_COPY([gl_header], [gl_cv_absolute_]AS_TR_SH(gl_HEADER_NAME))
+          AS_VAR_SET([gl_next_header], ['"'$gl_header'"'])
           m4_if([$2], [check],
             [else
-               AS_VAR_SET(gl_next_header, ['<'gl_HEADER_NAME'>'])
+               AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
              fi
             ])
          ])
      fi
      AC_SUBST(
        AS_TR_CPP([NEXT_]m4_defn([gl_HEADER_NAME])),
-       [AS_VAR_GET(gl_next_header)])
+       [AS_VAR_GET([gl_next_header])])
      if test $gl_cv_have_include_next = yes || test $gl_cv_have_include_next = buggy; then
        # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include_next'
        gl_next_as_first_directive='<'gl_HEADER_NAME'>'
      else
        # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include'
-       gl_next_as_first_directive=AS_VAR_GET(gl_next_header)
+       gl_next_as_first_directive=AS_VAR_GET([gl_next_header])
      fi
      AC_SUBST(
        AS_TR_CPP([NEXT_AS_FIRST_DIRECTIVE_]m4_defn([gl_HEADER_NAME])),
diff --git a/gl/m4/inet_ntop.m4 b/gl/m4/inet_ntop.m4
index 476f063f..48822d69 100644
--- a/gl/m4/inet_ntop.m4
+++ b/gl/m4/inet_ntop.m4
@@ -1,5 +1,5 @@
-# inet_ntop.m4 serial 19
-dnl Copyright (C) 2005-2006, 2008-2013 Free Software Foundation, Inc.
+# inet_ntop.m4 serial 21
+dnl Copyright (C) 2005-2006, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -16,6 +16,7 @@ AC_DEFUN([gl_FUNC_INET_NTOP],
   dnl Most platforms that provide inet_ntop define it in libc.
   dnl Solaris 8..10 provide inet_ntop in libnsl instead.
   dnl Solaris 2.6..7 provide inet_ntop in libresolv instead.
+  dnl Haiku provides it in -lnetwork.
   dnl Native Windows provides it in -lws2_32 instead, with a declaration in
   dnl <ws2tcpip.h>, and it uses stdcall calling convention, not cdecl
   dnl (hence we cannot use AC_CHECK_FUNCS, AC_SEARCH_LIBS to find it).
@@ -23,19 +24,20 @@ AC_DEFUN([gl_FUNC_INET_NTOP],
   INET_NTOP_LIB=
   gl_PREREQ_SYS_H_WINSOCK2
   if test $HAVE_WINSOCK2_H = 1; then
+    dnl It needs to be overridden, because the stdcall calling convention
+    dnl is not compliant with POSIX.  Set REPLACE_INET_NTOP in order to avoid
+    dnl a name conflict at the linker level, even though the header file
+    dnl <ws2tcpip.h> declares inet_ntop only if _WIN32_WINNT >= 0x0600.
+    REPLACE_INET_NTOP=1
     AC_CHECK_DECLS([inet_ntop],,, [[#include <ws2tcpip.h>]])
     if test $ac_cv_have_decl_inet_ntop = yes; then
-      dnl It needs to be overridden, because the stdcall calling convention
-      dnl is not compliant with POSIX.
-      REPLACE_INET_NTOP=1
       INET_NTOP_LIB="-lws2_32"
     else
       HAVE_DECL_INET_NTOP=0
-      HAVE_INET_NTOP=0
     fi
   else
     gl_save_LIBS=$LIBS
-    AC_SEARCH_LIBS([inet_ntop], [nsl resolv], [],
+    AC_SEARCH_LIBS([inet_ntop], [nsl resolv network], [],
       [AC_CHECK_FUNCS([inet_ntop])
        if test $ac_cv_func_inet_ntop = no; then
          HAVE_INET_NTOP=0
diff --git a/gl/m4/intdiv0.m4 b/gl/m4/intdiv0.m4
deleted file mode 100644
index 74d0e80d..00000000
--- a/gl/m4/intdiv0.m4
+++ /dev/null
@@ -1,87 +0,0 @@
-# intdiv0.m4 serial 6 (gettext-0.18.2)
-dnl Copyright (C) 2002, 2007-2008, 2010-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-dnl From Bruno Haible.
-
-AC_DEFUN([gt_INTDIV0],
-[
-  AC_REQUIRE([AC_PROG_CC])dnl
-  AC_REQUIRE([AC_CANONICAL_HOST])dnl
-
-  AC_CACHE_CHECK([whether integer division by zero raises SIGFPE],
-    gt_cv_int_divbyzero_sigfpe,
-    [
-      gt_cv_int_divbyzero_sigfpe=
-changequote(,)dnl
-      case "$host_os" in
-        macos* | darwin[6-9]* | darwin[1-9][0-9]*)
-          # On Mac OS X 10.2 or newer, just assume the same as when cross-
-          # compiling. If we were to perform the real test, 1 Crash Report
-          # dialog window would pop up.
-          case "$host_cpu" in
-            i[34567]86 | x86_64)
-              gt_cv_int_divbyzero_sigfpe="guessing yes" ;;
-          esac
-          ;;
-      esac
-changequote([,])dnl
-      if test -z "$gt_cv_int_divbyzero_sigfpe"; then
-        AC_RUN_IFELSE(
-          [AC_LANG_SOURCE([[
-#include <stdlib.h>
-#include <signal.h>
-
-static void
-sigfpe_handler (int sig)
-{
-  /* Exit with code 0 if SIGFPE, with code 1 if any other signal.  */
-  exit (sig != SIGFPE);
-}
-
-int x = 1;
-int y = 0;
-int z;
-int nan;
-
-int main ()
-{
-  signal (SIGFPE, sigfpe_handler);
-/* IRIX and AIX (when "xlc -qcheck" is used) yield signal SIGTRAP.  */
-#if (defined (__sgi) || defined (_AIX)) && defined (SIGTRAP)
-  signal (SIGTRAP, sigfpe_handler);
-#endif
-/* Linux/SPARC yields signal SIGILL.  */
-#if defined (__sparc__) && defined (__linux__)
-  signal (SIGILL, sigfpe_handler);
-#endif
-
-  z = x / y;
-  nan = y / y;
-  exit (2);
-}
-]])],
-          [gt_cv_int_divbyzero_sigfpe=yes],
-          [gt_cv_int_divbyzero_sigfpe=no],
-          [
-            # Guess based on the CPU.
-changequote(,)dnl
-            case "$host_cpu" in
-              alpha* | i[34567]86 | x86_64 | m68k | s390*)
-                gt_cv_int_divbyzero_sigfpe="guessing yes";;
-              *)
-                gt_cv_int_divbyzero_sigfpe="guessing no";;
-            esac
-changequote([,])dnl
-          ])
-      fi
-    ])
-  case "$gt_cv_int_divbyzero_sigfpe" in
-    *yes) value=1;;
-    *) value=0;;
-  esac
-  AC_DEFINE_UNQUOTED([INTDIV0_RAISES_SIGFPE], [$value],
-    [Define if integer division by zero raises signal SIGFPE.])
-])
diff --git a/gl/m4/intl-thread-locale.m4 b/gl/m4/intl-thread-locale.m4
new file mode 100644
index 00000000..c2318995
--- /dev/null
+++ b/gl/m4/intl-thread-locale.m4
@@ -0,0 +1,219 @@
+# intl-thread-locale.m4 serial 9
+dnl Copyright (C) 2015-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+dnl
+dnl This file can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Lesser General Public
+dnl License but which still want to provide support for the GNU gettext
+dnl functionality.
+dnl Please note that the actual code of the GNU gettext library is covered
+dnl by the GNU Lesser General Public License, and the rest of the GNU
+dnl gettext package is covered by the GNU General Public License.
+dnl They are *not* in the public domain.
+
+dnl Check how to retrieve the name of a per-thread locale (POSIX locale_t).
+dnl Sets gt_nameless_locales.
+AC_DEFUN([gt_INTL_THREAD_LOCALE_NAME],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  dnl Persuade Solaris <locale.h> to define 'locale_t'.
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  dnl Test whether uselocale() exists and works at all.
+  gt_FUNC_USELOCALE
+
+  dnl On OpenBSD >= 6.2, the locale_t type and the uselocale(), newlocale(),
+  dnl duplocale(), freelocale() functions exist but are effectively useless,
+  dnl because the locale_t value depends only on the LC_CTYPE category of the
+  dnl locale and furthermore contains only one bit of information (it
+  dnl distinguishes the "C" locale from the *.UTF-8 locales). See
+  dnl <https://cvsweb.openbsd.org/src/lib/libc/locale/newlocale.c?rev=1.1&content-type=text/x-cvsweb-markup>.
+  dnl In the setlocale() implementation they have thought about the programs
+  dnl that use the API ("Even though only LC_CTYPE has any effect in the
+  dnl OpenBSD base system, store complete information about the global locale,
+  dnl such that third-party software can access it"), but for uselocale()
+  dnl they did not think about the programs.
+  dnl In this situation, even the HAVE_NAMELESS_LOCALES support does not work.
+  dnl So, define HAVE_FAKE_LOCALES and disable all locale_t support.
+  case "$gt_cv_func_uselocale_works" in
+    *yes)
+      AC_CHECK_HEADERS_ONCE([xlocale.h])
+      AC_CACHE_CHECK([for fake locale system (OpenBSD)],
+        [gt_cv_locale_fake],
+        [AC_RUN_IFELSE(
+           [AC_LANG_SOURCE([[
+#include <locale.h>
+#if HAVE_XLOCALE_H
+# include <xlocale.h>
+#endif
+int main ()
+{
+  locale_t loc1, loc2;
+  if (setlocale (LC_ALL, "de_DE.UTF-8") == NULL) return 1;
+  if (setlocale (LC_ALL, "fr_FR.UTF-8") == NULL) return 1;
+  loc1 = newlocale (LC_ALL_MASK, "de_DE.UTF-8", (locale_t)0);
+  loc2 = newlocale (LC_ALL_MASK, "fr_FR.UTF-8", (locale_t)0);
+  return !(loc1 == loc2);
+}]])],
+           [gt_cv_locale_fake=yes],
+           [gt_cv_locale_fake=no],
+           [dnl Guess the locale system is fake only on OpenBSD.
+            case "$host_os" in
+              openbsd*) gt_cv_locale_fake="guessing yes" ;;
+              *)        gt_cv_locale_fake="guessing no" ;;
+            esac
+           ])
+        ])
+      ;;
+    *) gt_cv_locale_fake=no ;;
+  esac
+  case "$gt_cv_locale_fake" in
+    *yes)
+      gt_fake_locales=yes
+      AC_DEFINE([HAVE_FAKE_LOCALES], [1],
+        [Define if the locale_t type contains insufficient information, as on OpenBSD.])
+      ;;
+    *)
+      gt_fake_locales=no
+      ;;
+  esac
+
+  case "$gt_cv_func_uselocale_works" in
+    *yes)
+      AC_CACHE_CHECK([for Solaris 11.4 locale system],
+        [gt_cv_locale_solaris114],
+        [case "$host_os" in
+           solaris*)
+             dnl Test whether <locale.h> defines locale_t as a typedef of
+             dnl 'struct _LC_locale_t **' (whereas Illumos defines it as a
+             dnl typedef of 'struct _locale *').
+             dnl Another possible test would be to include <sys/localedef.h>
+             dnl and test whether it defines the _LC_core_data_locale_t type.
+             dnl This type was added in Solaris 11.4.
+             AC_COMPILE_IFELSE(
+               [AC_LANG_PROGRAM([[
+                  #include <locale.h>
+                  struct _LC_locale_t *x;
+                  locale_t y;
+                ]],
+                [[*y = x;]])],
+               [gt_cv_locale_solaris114=yes],
+               [gt_cv_locale_solaris114=no])
+             ;;
+           *) gt_cv_locale_solaris114=no ;;
+         esac
+        ])
+      ;;
+    *) gt_cv_locale_solaris114=no ;;
+  esac
+  if test $gt_cv_locale_solaris114 = yes; then
+    AC_DEFINE([HAVE_SOLARIS114_LOCALES], [1],
+      [Define if the locale_t type is as on Solaris 11.4.])
+  fi
+
+  dnl Solaris 12 will maybe provide getlocalename_l.  If it does, it will
+  dnl improve the implementation of gl_locale_name_thread(), by removing
+  dnl the use of undocumented structures.
+  case "$gt_cv_func_uselocale_works" in
+    *yes)
+      AC_CHECK_FUNCS([getlocalename_l])
+      ;;
+  esac
+
+  dnl This code is for platforms where the locale_t type does not provide access
+  dnl to the name of each locale category.  This code has the drawback that it
+  dnl requires the gnulib overrides of 'newlocale', 'duplocale', 'freelocale',
+  dnl which is a problem for GNU libunistring.  Therefore try hard to avoid
+  dnl enabling this code!
+  gt_nameless_locales=no
+  case "$host_os" in
+    dnl It's needed on AIX 7.2.
+    aix*)
+      gt_nameless_locales=yes
+      AC_DEFINE([HAVE_NAMELESS_LOCALES], [1],
+        [Define if the locale_t type does not contain the name of each locale category.])
+      ;;
+  esac
+
+  dnl We cannot support uselocale() on platforms where the locale_t type is
+  dnl fake.  So, set
+  dnl   gt_good_uselocale = gt_working_uselocale && !gt_fake_locales.
+  if test $gt_working_uselocale = yes && test $gt_fake_locales = no; then
+    gt_good_uselocale=yes
+    AC_DEFINE([HAVE_GOOD_USELOCALE], [1],
+      [Define if the uselocale exists, may be safely called, and returns sufficient information.])
+  else
+    gt_good_uselocale=no
+  fi
+
+  dnl Set gt_localename_enhances_locale_funcs to indicate whether localename.c
+  dnl overrides newlocale(), duplocale(), freelocale() to keep track of locale
+  dnl names.
+  if test $gt_good_uselocale = yes && test $gt_nameless_locales = yes; then
+    gt_localename_enhances_locale_funcs=yes
+    LOCALENAME_ENHANCE_LOCALE_FUNCS=1
+    AC_DEFINE([LOCALENAME_ENHANCE_LOCALE_FUNCS], [1],
+      [Define if localename.c overrides newlocale(), duplocale(), freelocale().])
+  else
+    gt_localename_enhances_locale_funcs=no
+  fi
+])
+
+dnl Tests whether uselocale() exists and is usable.
+dnl Sets gt_working_uselocale and defines HAVE_WORKING_USELOCALE.
+AC_DEFUN([gt_FUNC_USELOCALE],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  dnl Persuade glibc and Solaris <locale.h> to define 'locale_t'.
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_FUNCS_ONCE([uselocale])
+
+  dnl On AIX 7.2, the uselocale() function is not documented and leads to
+  dnl crashes in subsequent setlocale() invocations.
+  dnl In 2019, some versions of z/OS lack the locale_t type and have a broken
+  dnl uselocale function.
+  if test $ac_cv_func_uselocale = yes; then
+    AC_CHECK_HEADERS_ONCE([xlocale.h])
+    AC_CACHE_CHECK([whether uselocale works],
+      [gt_cv_func_uselocale_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_SOURCE([[
+#include <locale.h>
+#if HAVE_XLOCALE_H
+# include <xlocale.h>
+#endif
+locale_t loc1;
+int main ()
+{
+  uselocale (NULL);
+  setlocale (LC_ALL, "en_US.UTF-8");
+  return 0;
+}]])],
+         [gt_cv_func_uselocale_works=yes],
+         [gt_cv_func_uselocale_works=no],
+         [# Guess no on AIX and z/OS, yes otherwise.
+          case "$host_os" in
+            aix* | openedition*) gt_cv_func_uselocale_works="guessing no" ;;
+            *)                   gt_cv_func_uselocale_works="guessing yes" ;;
+          esac
+         ])
+      ])
+  else
+    gt_cv_func_uselocale_works=no
+  fi
+  case "$gt_cv_func_uselocale_works" in
+    *yes)
+      gt_working_uselocale=yes
+      AC_DEFINE([HAVE_WORKING_USELOCALE], [1],
+        [Define if the uselocale function exists and may safely be called.])
+      ;;
+    *)
+      gt_working_uselocale=no
+      ;;
+  esac
+])
diff --git a/gl/m4/intl.m4 b/gl/m4/intl.m4
deleted file mode 100644
index 959bd042..00000000
--- a/gl/m4/intl.m4
+++ /dev/null
@@ -1,271 +0,0 @@
-# intl.m4 serial 23 (gettext-0.18.3)
-dnl Copyright (C) 1995-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-dnl
-dnl This file can can be used in projects which are not available under
-dnl the GNU General Public License or the GNU Library General Public
-dnl License but which still want to provide support for the GNU gettext
-dnl functionality.
-dnl Please note that the actual code of the GNU gettext library is covered
-dnl by the GNU Library General Public License, and the rest of the GNU
-dnl gettext package package is covered by the GNU General Public License.
-dnl They are *not* in the public domain.
-
-dnl Authors:
-dnl   Ulrich Drepper <drepper@cygnus.com>, 1995-2000.
-dnl   Bruno Haible <haible@clisp.cons.org>, 2000-2009.
-
-AC_PREREQ([2.60])
-
-dnl Checks for all prerequisites of the intl subdirectory,
-dnl except for INTL_LIBTOOL_SUFFIX_PREFIX (and possibly LIBTOOL), INTLOBJS,
-dnl            USE_INCLUDED_LIBINTL, BUILD_INCLUDED_LIBINTL.
-AC_DEFUN([AM_INTL_SUBDIR],
-[
-  AC_REQUIRE([AC_PROG_INSTALL])dnl
-  AC_REQUIRE([AC_PROG_MKDIR_P])dnl
-  AC_REQUIRE([AC_PROG_CC])dnl
-  AC_REQUIRE([AC_CANONICAL_HOST])dnl
-  AC_REQUIRE([gt_GLIBC2])dnl
-  AC_REQUIRE([AC_PROG_RANLIB])dnl
-  AC_REQUIRE([gl_VISIBILITY])dnl
-  AC_REQUIRE([gt_INTL_SUBDIR_CORE])dnl
-  AC_REQUIRE([AC_TYPE_LONG_LONG_INT])dnl
-  AC_REQUIRE([gt_TYPE_WCHAR_T])dnl
-  AC_REQUIRE([gt_TYPE_WINT_T])dnl
-  AC_REQUIRE([gl_AC_HEADER_INTTYPES_H])
-  AC_REQUIRE([gt_TYPE_INTMAX_T])
-  AC_REQUIRE([gt_PRINTF_POSIX])
-  AC_REQUIRE([gl_GLIBC21])dnl
-  AC_REQUIRE([gl_XSIZE])dnl
-  AC_REQUIRE([gl_FCNTL_O_FLAGS])dnl
-  AC_REQUIRE([gt_INTL_MACOSX])dnl
-
-  dnl Support for automake's --enable-silent-rules.
-  case "$enable_silent_rules" in
-    yes) INTL_DEFAULT_VERBOSITY=0;;
-    no)  INTL_DEFAULT_VERBOSITY=1;;
-    *)   INTL_DEFAULT_VERBOSITY=1;;
-  esac
-  AC_SUBST([INTL_DEFAULT_VERBOSITY])
-
-  AC_CHECK_TYPE([ptrdiff_t], ,
-    [AC_DEFINE([ptrdiff_t], [long],
-       [Define as the type of the result of subtracting two pointers, if the system doesn't define it.])
-    ])
-  AC_CHECK_HEADERS([features.h stddef.h stdlib.h string.h])
-  AC_CHECK_FUNCS([asprintf fwprintf newlocale putenv setenv setlocale \
-    snprintf strnlen wcslen wcsnlen mbrtowc wcrtomb])
-
-  dnl Use the _snprintf function only if it is declared (because on NetBSD it
-  dnl is defined as a weak alias of snprintf; we prefer to use the latter).
-  AC_CHECK_DECLS([_snprintf _snwprintf], , , [#include <stdio.h>])
-
-  dnl Use the *_unlocked functions only if they are declared.
-  dnl (because some of them were defined without being declared in Solaris
-  dnl 2.5.1 but were removed in Solaris 2.6, whereas we want binaries built
-  dnl on Solaris 2.5.1 to run on Solaris 2.6).
-  AC_CHECK_DECLS([getc_unlocked], , , [#include <stdio.h>])
-
-  case $gt_cv_func_printf_posix in
-    *yes) HAVE_POSIX_PRINTF=1 ;;
-    *) HAVE_POSIX_PRINTF=0 ;;
-  esac
-  AC_SUBST([HAVE_POSIX_PRINTF])
-  if test "$ac_cv_func_asprintf" = yes; then
-    HAVE_ASPRINTF=1
-  else
-    HAVE_ASPRINTF=0
-  fi
-  AC_SUBST([HAVE_ASPRINTF])
-  if test "$ac_cv_func_snprintf" = yes; then
-    HAVE_SNPRINTF=1
-  else
-    HAVE_SNPRINTF=0
-  fi
-  AC_SUBST([HAVE_SNPRINTF])
-  if test "$ac_cv_func_newlocale" = yes; then
-    HAVE_NEWLOCALE=1
-  else
-    HAVE_NEWLOCALE=0
-  fi
-  AC_SUBST([HAVE_NEWLOCALE])
-  if test "$ac_cv_func_wprintf" = yes; then
-    HAVE_WPRINTF=1
-  else
-    HAVE_WPRINTF=0
-  fi
-  AC_SUBST([HAVE_WPRINTF])
-
-  AM_LANGINFO_CODESET
-  gt_LC_MESSAGES
-
-  dnl Compilation on mingw and Cygwin needs special Makefile rules, because
-  dnl 1. when we install a shared library, we must arrange to export
-  dnl    auxiliary pointer variables for every exported variable,
-  dnl 2. when we install a shared library and a static library simultaneously,
-  dnl    the include file specifies __declspec(dllimport) and therefore we
-  dnl    must arrange to define the auxiliary pointer variables for the
-  dnl    exported variables _also_ in the static library.
-  if test "$enable_shared" = yes; then
-    case "$host_os" in
-      mingw* | cygwin*) is_woe32dll=yes ;;
-      *) is_woe32dll=no ;;
-    esac
-  else
-    is_woe32dll=no
-  fi
-  WOE32DLL=$is_woe32dll
-  AC_SUBST([WOE32DLL])
-
-  dnl On mingw and Cygwin, we can activate special Makefile rules which add
-  dnl version information to the shared libraries and executables.
-  case "$host_os" in
-    mingw* | cygwin*) is_woe32=yes ;;
-    *) is_woe32=no ;;
-  esac
-  WOE32=$is_woe32
-  AC_SUBST([WOE32])
-  if test $WOE32 = yes; then
-    dnl Check for a program that compiles Windows resource files.
-    AC_CHECK_TOOL([WINDRES], [windres])
-  fi
-
-  dnl Determine whether when creating a library, "-lc" should be passed to
-  dnl libtool or not. On many platforms, it is required for the libtool option
-  dnl -no-undefined to work. On HP-UX, however, the -lc - stored by libtool
-  dnl in the *.la files - makes it impossible to create multithreaded programs,
-  dnl because libtool also reorders the -lc to come before the -pthread, and
-  dnl this disables pthread_create() <http://docs.hp.com/en/1896/pthreads.html>.
-  case "$host_os" in
-    hpux*) LTLIBC="" ;;
-    *)     LTLIBC="-lc" ;;
-  esac
-  AC_SUBST([LTLIBC])
-
-  dnl Rename some macros and functions used for locking.
-  AH_BOTTOM([
-#define __libc_lock_t                   gl_lock_t
-#define __libc_lock_define              gl_lock_define
-#define __libc_lock_define_initialized  gl_lock_define_initialized
-#define __libc_lock_init                gl_lock_init
-#define __libc_lock_lock                gl_lock_lock
-#define __libc_lock_unlock              gl_lock_unlock
-#define __libc_lock_recursive_t                   gl_recursive_lock_t
-#define __libc_lock_define_recursive              gl_recursive_lock_define
-#define __libc_lock_define_initialized_recursive  gl_recursive_lock_define_initialized
-#define __libc_lock_init_recursive                gl_recursive_lock_init
-#define __libc_lock_lock_recursive                gl_recursive_lock_lock
-#define __libc_lock_unlock_recursive              gl_recursive_lock_unlock
-#define glthread_in_use  libintl_thread_in_use
-#define glthread_lock_init_func     libintl_lock_init_func
-#define glthread_lock_lock_func     libintl_lock_lock_func
-#define glthread_lock_unlock_func   libintl_lock_unlock_func
-#define glthread_lock_destroy_func  libintl_lock_destroy_func
-#define glthread_rwlock_init_multithreaded     libintl_rwlock_init_multithreaded
-#define glthread_rwlock_init_func              libintl_rwlock_init_func
-#define glthread_rwlock_rdlock_multithreaded   libintl_rwlock_rdlock_multithreaded
-#define glthread_rwlock_rdlock_func            libintl_rwlock_rdlock_func
-#define glthread_rwlock_wrlock_multithreaded   libintl_rwlock_wrlock_multithreaded
-#define glthread_rwlock_wrlock_func            libintl_rwlock_wrlock_func
-#define glthread_rwlock_unlock_multithreaded   libintl_rwlock_unlock_multithreaded
-#define glthread_rwlock_unlock_func            libintl_rwlock_unlock_func
-#define glthread_rwlock_destroy_multithreaded  libintl_rwlock_destroy_multithreaded
-#define glthread_rwlock_destroy_func           libintl_rwlock_destroy_func
-#define glthread_recursive_lock_init_multithreaded     libintl_recursive_lock_init_multithreaded
-#define glthread_recursive_lock_init_func              libintl_recursive_lock_init_func
-#define glthread_recursive_lock_lock_multithreaded     libintl_recursive_lock_lock_multithreaded
-#define glthread_recursive_lock_lock_func              libintl_recursive_lock_lock_func
-#define glthread_recursive_lock_unlock_multithreaded   libintl_recursive_lock_unlock_multithreaded
-#define glthread_recursive_lock_unlock_func            libintl_recursive_lock_unlock_func
-#define glthread_recursive_lock_destroy_multithreaded  libintl_recursive_lock_destroy_multithreaded
-#define glthread_recursive_lock_destroy_func           libintl_recursive_lock_destroy_func
-#define glthread_once_func            libintl_once_func
-#define glthread_once_singlethreaded  libintl_once_singlethreaded
-#define glthread_once_multithreaded   libintl_once_multithreaded
-])
-])
-
-
-dnl Checks for the core files of the intl subdirectory:
-dnl   dcigettext.c
-dnl   eval-plural.h
-dnl   explodename.c
-dnl   finddomain.c
-dnl   gettextP.h
-dnl   gmo.h
-dnl   hash-string.h hash-string.c
-dnl   l10nflist.c
-dnl   libgnuintl.h.in (except the *printf stuff)
-dnl   loadinfo.h
-dnl   loadmsgcat.c
-dnl   localealias.c
-dnl   log.c
-dnl   plural-exp.h plural-exp.c
-dnl   plural.y
-dnl Used by libglocale.
-AC_DEFUN([gt_INTL_SUBDIR_CORE],
-[
-  AC_REQUIRE([AC_C_INLINE])dnl
-  AC_REQUIRE([AC_TYPE_SIZE_T])dnl
-  AC_REQUIRE([gl_AC_HEADER_STDINT_H])
-  AC_REQUIRE([AC_FUNC_ALLOCA])dnl
-  AC_REQUIRE([AC_FUNC_MMAP])dnl
-  AC_REQUIRE([gt_INTDIV0])dnl
-  AC_REQUIRE([gl_AC_TYPE_UINTMAX_T])dnl
-  AC_REQUIRE([gt_INTTYPES_PRI])dnl
-  AC_REQUIRE([gl_LOCK])dnl
-
-  AC_LINK_IFELSE(
-    [AC_LANG_PROGRAM(
-       [[int foo (int a) { a = __builtin_expect (a, 10); return a == 10 ? 0 : 1; }]],
-       [[]])],
-    [AC_DEFINE([HAVE_BUILTIN_EXPECT], [1],
-       [Define to 1 if the compiler understands __builtin_expect.])])
-
-  AC_CHECK_HEADERS([argz.h inttypes.h limits.h unistd.h sys/param.h])
-  AC_CHECK_FUNCS([getcwd getegid geteuid getgid getuid mempcpy munmap \
-    stpcpy strcasecmp strdup strtoul tsearch uselocale argz_count \
-    argz_stringify argz_next __fsetlocking])
-
-  dnl Use the *_unlocked functions only if they are declared.
-  dnl (because some of them were defined without being declared in Solaris
-  dnl 2.5.1 but were removed in Solaris 2.6, whereas we want binaries built
-  dnl on Solaris 2.5.1 to run on Solaris 2.6).
-  AC_CHECK_DECLS([feof_unlocked fgets_unlocked], , , [#include <stdio.h>])
-
-  AM_ICONV
-
-  dnl intl/plural.c is generated from intl/plural.y. It requires bison,
-  dnl because plural.y uses bison specific features. It requires at least
-  dnl bison-1.26 because earlier versions generate a plural.c that doesn't
-  dnl compile.
-  dnl bison is only needed for the maintainer (who touches plural.y). But in
-  dnl order to avoid separate Makefiles or --enable-maintainer-mode, we put
-  dnl the rule in general Makefile. Now, some people carelessly touch the
-  dnl files or have a broken "make" program, hence the plural.c rule will
-  dnl sometimes fire. To avoid an error, defines BISON to ":" if it is not
-  dnl present or too old.
-  AC_CHECK_PROGS([INTLBISON], [bison])
-  if test -z "$INTLBISON"; then
-    ac_verc_fail=yes
-  else
-    dnl Found it, now check the version.
-    AC_MSG_CHECKING([version of bison])
-changequote(<<,>>)dnl
-    ac_prog_version=`$INTLBISON --version 2>&1 | sed -n 's/^.*GNU Bison.* \([0-9]*\.[0-9.]*\).*$/\1/p'`
-    case $ac_prog_version in
-      '') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;
-      1.2[6-9]* | 1.[3-9][0-9]* | [2-9].*)
-changequote([,])dnl
-         ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;
-      *) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;
-    esac
-    AC_MSG_RESULT([$ac_prog_version])
-  fi
-  if test $ac_verc_fail = yes; then
-    INTLBISON=:
-  fi
-])
diff --git a/gl/m4/intldir.m4 b/gl/m4/intldir.m4
deleted file mode 100644
index 388ecd6f..00000000
--- a/gl/m4/intldir.m4
+++ /dev/null
@@ -1,19 +0,0 @@
-# intldir.m4 serial 2 (gettext-0.18)
-dnl Copyright (C) 2006, 2009-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-dnl
-dnl This file can can be used in projects which are not available under
-dnl the GNU General Public License or the GNU Library General Public
-dnl License but which still want to provide support for the GNU gettext
-dnl functionality.
-dnl Please note that the actual code of the GNU gettext library is covered
-dnl by the GNU Library General Public License, and the rest of the GNU
-dnl gettext package package is covered by the GNU General Public License.
-dnl They are *not* in the public domain.
-
-AC_PREREQ([2.52])
-
-dnl Tells the AM_GNU_GETTEXT macro to consider an intl/ directory.
-AC_DEFUN([AM_GNU_GETTEXT_INTL_SUBDIR], [])
diff --git a/gl/m4/intlmacosx.m4 b/gl/m4/intlmacosx.m4
index ab97d39f..81eefd75 100644
--- a/gl/m4/intlmacosx.m4
+++ b/gl/m4/intlmacosx.m4
@@ -1,23 +1,23 @@
-# intlmacosx.m4 serial 5 (gettext-0.18.2)
-dnl Copyright (C) 2004-2013 Free Software Foundation, Inc.
+# intlmacosx.m4 serial 8 (gettext-0.20.2)
+dnl Copyright (C) 2004-2014, 2016, 2019-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 dnl
-dnl This file can can be used in projects which are not available under
-dnl the GNU General Public License or the GNU Library General Public
+dnl This file can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Lesser General Public
 dnl License but which still want to provide support for the GNU gettext
 dnl functionality.
 dnl Please note that the actual code of the GNU gettext library is covered
-dnl by the GNU Library General Public License, and the rest of the GNU
-dnl gettext package package is covered by the GNU General Public License.
+dnl by the GNU Lesser General Public License, and the rest of the GNU
+dnl gettext package is covered by the GNU General Public License.
 dnl They are *not* in the public domain.
 
 dnl Checks for special options needed on Mac OS X.
 dnl Defines INTL_MACOSX_LIBS.
 AC_DEFUN([gt_INTL_MACOSX],
 [
-  dnl Check for API introduced in Mac OS X 10.2.
+  dnl Check for API introduced in Mac OS X 10.4.
   AC_CACHE_CHECK([for CFPreferencesCopyAppValue],
     [gt_cv_func_CFPreferencesCopyAppValue],
     [gt_save_LIBS="$LIBS"
@@ -33,23 +33,32 @@ AC_DEFUN([gt_INTL_MACOSX],
     AC_DEFINE([HAVE_CFPREFERENCESCOPYAPPVALUE], [1],
       [Define to 1 if you have the Mac OS X function CFPreferencesCopyAppValue in the CoreFoundation framework.])
   fi
-  dnl Check for API introduced in Mac OS X 10.3.
-  AC_CACHE_CHECK([for CFLocaleCopyCurrent], [gt_cv_func_CFLocaleCopyCurrent],
+  dnl Don't check for the API introduced in Mac OS X 10.5, CFLocaleCopyCurrent,
+  dnl because in macOS 10.13.4 it has the following behaviour:
+  dnl When two or more languages are specified in the
+  dnl "System Preferences > Language & Region > Preferred Languages" panel,
+  dnl it returns en_CC where CC is the territory (even when English is not among
+  dnl the preferred languages!).  What we want instead is what
+  dnl CFLocaleCopyCurrent returned in earlier macOS releases and what
+  dnl CFPreferencesCopyAppValue still returns, namely ll_CC where ll is the
+  dnl first among the preferred languages and CC is the territory.
+  AC_CACHE_CHECK([for CFLocaleCopyPreferredLanguages], [gt_cv_func_CFLocaleCopyPreferredLanguages],
     [gt_save_LIBS="$LIBS"
      LIBS="$LIBS -Wl,-framework -Wl,CoreFoundation"
      AC_LINK_IFELSE(
        [AC_LANG_PROGRAM(
           [[#include <CoreFoundation/CFLocale.h>]],
-          [[CFLocaleCopyCurrent();]])],
-       [gt_cv_func_CFLocaleCopyCurrent=yes],
-       [gt_cv_func_CFLocaleCopyCurrent=no])
+          [[CFLocaleCopyPreferredLanguages();]])],
+       [gt_cv_func_CFLocaleCopyPreferredLanguages=yes],
+       [gt_cv_func_CFLocaleCopyPreferredLanguages=no])
      LIBS="$gt_save_LIBS"])
-  if test $gt_cv_func_CFLocaleCopyCurrent = yes; then
-    AC_DEFINE([HAVE_CFLOCALECOPYCURRENT], [1],
-      [Define to 1 if you have the Mac OS X function CFLocaleCopyCurrent in the CoreFoundation framework.])
+  if test $gt_cv_func_CFLocaleCopyPreferredLanguages = yes; then
+    AC_DEFINE([HAVE_CFLOCALECOPYPREFERREDLANGUAGES], [1],
+      [Define to 1 if you have the Mac OS X function CFLocaleCopyPreferredLanguages in the CoreFoundation framework.])
   fi
   INTL_MACOSX_LIBS=
-  if test $gt_cv_func_CFPreferencesCopyAppValue = yes || test $gt_cv_func_CFLocaleCopyCurrent = yes; then
+  if test $gt_cv_func_CFPreferencesCopyAppValue = yes \
+     || test $gt_cv_func_CFLocaleCopyPreferredLanguages = yes; then
     INTL_MACOSX_LIBS="-Wl,-framework -Wl,CoreFoundation"
   fi
   AC_SUBST([INTL_MACOSX_LIBS])
diff --git a/gl/m4/intmax.m4 b/gl/m4/intmax.m4
deleted file mode 100644
index 18733a52..00000000
--- a/gl/m4/intmax.m4
+++ /dev/null
@@ -1,36 +0,0 @@
-# intmax.m4 serial 6 (gettext-0.18.2)
-dnl Copyright (C) 2002-2005, 2008-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-dnl From Bruno Haible.
-dnl Test whether the system has the 'intmax_t' type, but don't attempt to
-dnl find a replacement if it is lacking.
-
-AC_DEFUN([gt_TYPE_INTMAX_T],
-[
-  AC_REQUIRE([gl_AC_HEADER_INTTYPES_H])
-  AC_REQUIRE([gl_AC_HEADER_STDINT_H])
-  AC_CACHE_CHECK([for intmax_t], [gt_cv_c_intmax_t],
-    [AC_COMPILE_IFELSE(
-       [AC_LANG_PROGRAM(
-          [[
-#include <stddef.h>
-#include <stdlib.h>
-#if HAVE_STDINT_H_WITH_UINTMAX
-#include <stdint.h>
-#endif
-#if HAVE_INTTYPES_H_WITH_UINTMAX
-#include <inttypes.h>
-#endif
-          ]],
-          [[intmax_t x = -1;
-            return !x;]])],
-       [gt_cv_c_intmax_t=yes],
-       [gt_cv_c_intmax_t=no])])
-  if test $gt_cv_c_intmax_t = yes; then
-    AC_DEFINE([HAVE_INTMAX_T], [1],
-      [Define if you have the 'intmax_t' type in <stdint.h> or <inttypes.h>.])
-  fi
-])
diff --git a/gl/m4/intmax_t.m4 b/gl/m4/intmax_t.m4
index 6ea70531..ef32e1b9 100644
--- a/gl/m4/intmax_t.m4
+++ b/gl/m4/intmax_t.m4
@@ -1,5 +1,5 @@
-# intmax_t.m4 serial 8
-dnl Copyright (C) 1997-2004, 2006-2007, 2009-2013 Free Software Foundation,
+# intmax_t.m4 serial 9
+dnl Copyright (C) 1997-2004, 2006-2007, 2009-2023 Free Software Foundation,
 dnl Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -19,11 +19,7 @@ AC_DEFUN([gl_AC_TYPE_INTMAX_T],
   AC_REQUIRE([gl_AC_HEADER_INTTYPES_H])
   AC_REQUIRE([gl_AC_HEADER_STDINT_H])
   if test $gl_cv_header_inttypes_h = no && test $gl_cv_header_stdint_h = no; then
-    AC_REQUIRE([AC_TYPE_LONG_LONG_INT])
-    test $ac_cv_type_long_long_int = yes \
-      && ac_type='long long' \
-      || ac_type='long'
-    AC_DEFINE_UNQUOTED([intmax_t], [$ac_type],
+    AC_DEFINE_UNQUOTED([intmax_t], [long long],
      [Define to long or long long if <inttypes.h> and <stdint.h> don't define.])
   else
     AC_DEFINE([HAVE_INTMAX_T], [1],
@@ -57,11 +53,7 @@ AC_DEFUN([gt_AC_TYPE_INTMAX_T],
     AC_DEFINE([HAVE_INTMAX_T], [1],
       [Define if you have the 'intmax_t' type in <stdint.h> or <inttypes.h>.])
   else
-    AC_REQUIRE([AC_TYPE_LONG_LONG_INT])
-    test $ac_cv_type_long_long_int = yes \
-      && ac_type='long long' \
-      || ac_type='long'
-    AC_DEFINE_UNQUOTED([intmax_t], [$ac_type],
+    AC_DEFINE_UNQUOTED([intmax_t], [long long],
      [Define to long or long long if <stdint.h> and <inttypes.h> don't define.])
   fi
 ])
diff --git a/gl/m4/inttypes-pri.m4 b/gl/m4/inttypes-pri.m4
deleted file mode 100644
index e5a1e057..00000000
--- a/gl/m4/inttypes-pri.m4
+++ /dev/null
@@ -1,42 +0,0 @@
-# inttypes-pri.m4 serial 7 (gettext-0.18.2)
-dnl Copyright (C) 1997-2002, 2006, 2008-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-dnl From Bruno Haible.
-
-AC_PREREQ([2.53])
-
-# Define PRI_MACROS_BROKEN if <inttypes.h> exists and defines the PRI*
-# macros to non-string values.  This is the case on AIX 4.3.3.
-
-AC_DEFUN([gt_INTTYPES_PRI],
-[
-  AC_CHECK_HEADERS([inttypes.h])
-  if test $ac_cv_header_inttypes_h = yes; then
-    AC_CACHE_CHECK([whether the inttypes.h PRIxNN macros are broken],
-      [gt_cv_inttypes_pri_broken],
-      [
-        AC_COMPILE_IFELSE(
-          [AC_LANG_PROGRAM(
-             [[
-#include <inttypes.h>
-#ifdef PRId32
-char *p = PRId32;
-#endif
-             ]],
-             [[]])],
-          [gt_cv_inttypes_pri_broken=no],
-          [gt_cv_inttypes_pri_broken=yes])
-      ])
-  fi
-  if test "$gt_cv_inttypes_pri_broken" = yes; then
-    AC_DEFINE_UNQUOTED([PRI_MACROS_BROKEN], [1],
-      [Define if <inttypes.h> exists and defines unusable PRI* macros.])
-    PRI_MACROS_BROKEN=1
-  else
-    PRI_MACROS_BROKEN=0
-  fi
-  AC_SUBST([PRI_MACROS_BROKEN])
-])
diff --git a/gl/m4/inttypes.m4 b/gl/m4/inttypes.m4
new file mode 100644
index 00000000..bf2eab2b
--- /dev/null
+++ b/gl/m4/inttypes.m4
@@ -0,0 +1,180 @@
+# inttypes.m4 serial 36
+dnl Copyright (C) 2006-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Derek Price, Bruno Haible.
+dnl Test whether <inttypes.h> is supported or must be substituted.
+
+AC_DEFUN_ONCE([gl_INTTYPES_H],
+[
+  AC_REQUIRE([gl_INTTYPES_INCOMPLETE])
+  gl_INTTYPES_PRI_SCN
+])
+
+AC_DEFUN_ONCE([gl_INTTYPES_INCOMPLETE],
+[
+  AC_REQUIRE([gl_STDINT_H])
+  AC_CHECK_HEADERS_ONCE([inttypes.h])
+
+  dnl Override <inttypes.h> always, so that the portability warnings work.
+  AC_REQUIRE([gl_INTTYPES_H_DEFAULTS])
+  gl_CHECK_NEXT_HEADERS([inttypes.h])
+
+  AC_REQUIRE([gl_MULTIARCH])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <inttypes.h>
+    ]], [imaxabs imaxdiv strtoimax strtoumax])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+])
+
+# Ensure that the PRI* and SCN* macros are defined appropriately.
+AC_DEFUN([gl_INTTYPES_PRI_SCN],
+[
+  PRIPTR_PREFIX=
+  if $GL_GENERATE_STDINT_H; then
+    dnl Using the gnulib <stdint.h>. It defines intptr_t to 'long' or
+    dnl 'long long', depending on _WIN64.
+    AC_COMPILE_IFELSE(
+      [AC_LANG_PROGRAM([[
+         #ifdef _WIN64
+         LLP64
+         #endif
+         ]])
+      ],
+      [PRIPTR_PREFIX='"l"'],
+      [PRIPTR_PREFIX='"ll"'])
+  else
+    dnl Using the system's <stdint.h>.
+    for glpfx in '' l ll I64; do
+      case $glpfx in
+        '')  gltype1='int';;
+        l)   gltype1='long int';;
+        ll)  gltype1='long long int';;
+        I64) gltype1='__int64';;
+      esac
+      AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM([[#include <stdint.h>
+           extern intptr_t foo;
+           extern $gltype1 foo;]])],
+        [PRIPTR_PREFIX='"'$glpfx'"'])
+      test -n "$PRIPTR_PREFIX" && break
+    done
+  fi
+  AC_SUBST([PRIPTR_PREFIX])
+
+  gl_INTTYPES_CHECK_LONG_LONG_INT_CONDITION(
+    [INT32_MAX_LT_INTMAX_MAX],
+    [defined INT32_MAX && defined INTMAX_MAX],
+    [INT32_MAX < INTMAX_MAX],
+    [sizeof (int) < sizeof (long long int)])
+  if test $APPLE_UNIVERSAL_BUILD = 0; then
+    gl_INTTYPES_CHECK_LONG_LONG_INT_CONDITION(
+      [INT64_MAX_EQ_LONG_MAX],
+      [defined INT64_MAX],
+      [INT64_MAX == LONG_MAX],
+      [sizeof (long long int) == sizeof (long int)])
+  else
+    INT64_MAX_EQ_LONG_MAX=-1
+  fi
+  gl_INTTYPES_CHECK_LONG_LONG_INT_CONDITION(
+    [UINT32_MAX_LT_UINTMAX_MAX],
+    [defined UINT32_MAX && defined UINTMAX_MAX],
+    [UINT32_MAX < UINTMAX_MAX],
+    [sizeof (unsigned int) < sizeof (unsigned long long int)])
+  if test $APPLE_UNIVERSAL_BUILD = 0; then
+    gl_INTTYPES_CHECK_LONG_LONG_INT_CONDITION(
+      [UINT64_MAX_EQ_ULONG_MAX],
+      [defined UINT64_MAX],
+      [UINT64_MAX == ULONG_MAX],
+      [sizeof (unsigned long long int) == sizeof (unsigned long int)])
+  else
+    UINT64_MAX_EQ_ULONG_MAX=-1
+  fi
+])
+
+# Define the symbol $1 to be 1 if the condition is true, 0 otherwise.
+# If $2 is true, the condition is $3; otherwise if long long int is supported
+# approximate the condition with $4; otherwise, assume the condition is false.
+# The condition should work on all C99 platforms; the approximations should be
+# good enough to work on all practical pre-C99 platforms.
+# $2 is evaluated by the C preprocessor, $3 and $4 as compile-time constants.
+AC_DEFUN([gl_INTTYPES_CHECK_LONG_LONG_INT_CONDITION],
+[
+  AC_CACHE_CHECK([whether $3],
+    [gl_cv_test_$1],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[/* Work also in C++ mode.  */
+            #define __STDC_LIMIT_MACROS 1
+
+            /* Work if build is not clean.  */
+            #define _GL_JUST_INCLUDE_SYSTEM_STDINT_H
+
+            #include <limits.h>
+            #if HAVE_STDINT_H
+             #include <stdint.h>
+            #endif
+
+            #if $2
+             #define CONDITION ($3)
+            #else
+             #define CONDITION ($4)
+            #endif
+            int test[CONDITION ? 1 : -1];]])],
+       [gl_cv_test_$1=yes],
+       [gl_cv_test_$1=no])])
+  if test $gl_cv_test_$1 = yes; then
+    $1=1;
+  else
+    $1=0;
+  fi
+  AC_SUBST([$1])
+])
+
+# gl_INTTYPES_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
+AC_DEFUN([gl_INTTYPES_MODULE_INDICATOR],
+[
+  dnl Ensure to expand the default settings once only.
+  gl_INTTYPES_H_REQUIRE_DEFAULTS
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+])
+
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_INTTYPES_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_INTTYPES_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_IMAXABS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_IMAXDIV])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRTOIMAX])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRTOUMAX])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_INTTYPES_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_INTTYPES_H_DEFAULTS])
+])
+
+AC_DEFUN([gl_INTTYPES_H_DEFAULTS],
+[
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_DECL_IMAXABS=1;   AC_SUBST([HAVE_DECL_IMAXABS])
+  HAVE_DECL_IMAXDIV=1;   AC_SUBST([HAVE_DECL_IMAXDIV])
+  HAVE_DECL_STRTOIMAX=1; AC_SUBST([HAVE_DECL_STRTOIMAX])
+  HAVE_DECL_STRTOUMAX=1; AC_SUBST([HAVE_DECL_STRTOUMAX])
+  HAVE_IMAXDIV_T=1;      AC_SUBST([HAVE_IMAXDIV_T])
+  REPLACE_STRTOIMAX=0;   AC_SUBST([REPLACE_STRTOIMAX])
+  REPLACE_STRTOUMAX=0;   AC_SUBST([REPLACE_STRTOUMAX])
+  INT32_MAX_LT_INTMAX_MAX=1;  AC_SUBST([INT32_MAX_LT_INTMAX_MAX])
+  INT64_MAX_EQ_LONG_MAX='defined _LP64';  AC_SUBST([INT64_MAX_EQ_LONG_MAX])
+  PRIPTR_PREFIX=__PRIPTR_PREFIX;  AC_SUBST([PRIPTR_PREFIX])
+  UINT32_MAX_LT_UINTMAX_MAX=1;  AC_SUBST([UINT32_MAX_LT_UINTMAX_MAX])
+  UINT64_MAX_EQ_ULONG_MAX='defined _LP64';  AC_SUBST([UINT64_MAX_EQ_ULONG_MAX])
+])
diff --git a/gl/m4/inttypes_h.m4 b/gl/m4/inttypes_h.m4
index 5f05ac58..68c60e9d 100644
--- a/gl/m4/inttypes_h.m4
+++ b/gl/m4/inttypes_h.m4
@@ -1,5 +1,5 @@
 # inttypes_h.m4 serial 10
-dnl Copyright (C) 1997-2004, 2006, 2008-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 1997-2004, 2006, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/langinfo_h.m4 b/gl/m4/langinfo_h.m4
index 73bef8bc..b17a526a 100644
--- a/gl/m4/langinfo_h.m4
+++ b/gl/m4/langinfo_h.m4
@@ -1,10 +1,10 @@
-# langinfo_h.m4 serial 7
-dnl Copyright (C) 2009-2013 Free Software Foundation, Inc.
+# langinfo_h.m4 serial 12
+dnl Copyright (C) 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-AC_DEFUN([gl_LANGINFO_H],
+AC_DEFUN_ONCE([gl_LANGINFO_H],
 [
   AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
 
@@ -17,13 +17,17 @@ AC_DEFUN([gl_LANGINFO_H],
   dnl Determine whether <langinfo.h> exists. It is missing on mingw and BeOS.
   HAVE_LANGINFO_CODESET=0
   HAVE_LANGINFO_T_FMT_AMPM=0
+  HAVE_LANGINFO_ALTMON=0
   HAVE_LANGINFO_ERA=0
   HAVE_LANGINFO_YESEXPR=0
   AC_CHECK_HEADERS_ONCE([langinfo.h])
   if test $ac_cv_header_langinfo_h = yes; then
     HAVE_LANGINFO_H=1
-    dnl Determine what <langinfo.h> defines. CODESET and ERA etc. are missing
-    dnl on OpenBSD 3.8. T_FMT_AMPM and YESEXPR, NOEXPR are missing on IRIX 5.3.
+    dnl Determine what <langinfo.h> defines.
+    dnl CODESET is missing on OpenBSD 3.8.
+    dnl ERA etc. are missing on OpenBSD 6.7.
+    dnl T_FMT_AMPM and YESEXPR, NOEXPR are missing on IRIX 5.3.
+    dnl ALTMON_* are missing on glibc 2.26 and many other systems.
     AC_CACHE_CHECK([whether langinfo.h defines CODESET],
       [gl_cv_header_langinfo_codeset],
       [AC_COMPILE_IFELSE(
@@ -48,6 +52,18 @@ int a = T_FMT_AMPM;
     if test $gl_cv_header_langinfo_t_fmt_ampm = yes; then
       HAVE_LANGINFO_T_FMT_AMPM=1
     fi
+    AC_CACHE_CHECK([whether langinfo.h defines ALTMON_1],
+      [gl_cv_header_langinfo_altmon],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = ALTMON_1;
+]])],
+         [gl_cv_header_langinfo_altmon=yes],
+         [gl_cv_header_langinfo_altmon=no])
+      ])
+    if test $gl_cv_header_langinfo_altmon = yes; then
+      HAVE_LANGINFO_ALTMON=1
+    fi
     AC_CACHE_CHECK([whether langinfo.h defines ERA],
       [gl_cv_header_langinfo_era],
       [AC_COMPILE_IFELSE(
@@ -78,6 +94,7 @@ int a = YESEXPR;
   AC_SUBST([HAVE_LANGINFO_H])
   AC_SUBST([HAVE_LANGINFO_CODESET])
   AC_SUBST([HAVE_LANGINFO_T_FMT_AMPM])
+  AC_SUBST([HAVE_LANGINFO_ALTMON])
   AC_SUBST([HAVE_LANGINFO_ERA])
   AC_SUBST([HAVE_LANGINFO_YESEXPR])
 
@@ -87,18 +104,33 @@ int a = YESEXPR;
     ]], [nl_langinfo])
 ])
 
+# gl_LANGINFO_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_LANGINFO_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_LANGINFO_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_LANGINFO_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_LANGINFO_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_NL_LANGINFO])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_LANGINFO_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_LANGINFO_H_DEFAULTS],
 [
-  GNULIB_NL_LANGINFO=0;  AC_SUBST([GNULIB_NL_LANGINFO])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_NL_LANGINFO=1;    AC_SUBST([HAVE_NL_LANGINFO])
   REPLACE_NL_LANGINFO=0; AC_SUBST([REPLACE_NL_LANGINFO])
diff --git a/gl/m4/largefile.m4 b/gl/m4/largefile.m4
index 1e605e3d..7fb81b86 100644
--- a/gl/m4/largefile.m4
+++ b/gl/m4/largefile.m4
@@ -1,104 +1,319 @@
 # Enable large files on systems where this is not the default.
+# Enable support for files on Linux file systems with 64-bit inode numbers.
 
-# Copyright 1992-1996, 1998-2013 Free Software Foundation, Inc.
+# Copyright 1992-1996, 1998-2023 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
-# The following implementation works around a problem in autoconf <= 2.69;
+# The following macro works around a problem in Autoconf's AC_FUNC_FSEEKO:
+# It does not set _LARGEFILE_SOURCE=1 on HP-UX/ia64 32-bit, although this
+# setting of _LARGEFILE_SOURCE is needed so that <stdio.h> declares fseeko
+# and ftello in C++ mode as well.
+# Fixed in Autoconf 2.72, which has AC_SYS_YEAR2038.
+AC_DEFUN([gl_SET_LARGEFILE_SOURCE],
+ m4_ifndef([AC_SYS_YEAR2038], [[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_FUNC_FSEEKO
+  case "$host_os" in
+    hpux*)
+      AC_DEFINE([_LARGEFILE_SOURCE], [1],
+        [Define to 1 to make fseeko visible on some hosts (e.g. glibc 2.2).])
+      ;;
+  esac
+ ]])
+)
+
+# Work around a problem in autoconf <= 2.69:
 # AC_SYS_LARGEFILE does not configure for large inodes on Mac OS X 10.5,
 # or configures them incorrectly in some cases.
-m4_version_prereq([2.70], [] ,[
+m4_version_prereq([2.70], [], [
 
 # _AC_SYS_LARGEFILE_TEST_INCLUDES
 # -------------------------------
 m4_define([_AC_SYS_LARGEFILE_TEST_INCLUDES],
-[@%:@include <sys/types.h>
+[#include <sys/types.h>
  /* Check that off_t can represent 2**63 - 1 correctly.
     We can't simply define LARGE_OFF_T to be 9223372036854775807,
     since some C++ compilers masquerading as C compilers
     incorrectly reject 9223372036854775807.  */
-@%:@define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
+#define LARGE_OFF_T (((off_t) 1 << 31 << 31) - 1 + ((off_t) 1 << 31 << 31))
   int off_t_is_large[[(LARGE_OFF_T % 2147483629 == 721
                        && LARGE_OFF_T % 2147483647 == 1)
                       ? 1 : -1]];[]dnl
 ])
+])# m4_version_prereq 2.70
+
+# Support AC_SYS_YEAR2038, even if Autoconf 2.71 or earlier.
+# This code is taken from Autoconf master.
+m4_ifndef([AC_SYS_YEAR2038], [
+
+# _AC_SYS_YEAR2038_TEST_CODE
+# --------------------------
+# C code used to probe for time_t that can represent time points more
+# than 2**31 - 1 seconds after the epoch.  With the usual Unix epoch,
+# these correspond to dates after 2038-01-18 22:14:07 +0000 (Gregorian),
+# hence the name.
+AC_DEFUN([_AC_SYS_YEAR2038_TEST_CODE],
+[[
+  #include <time.h>
+  /* Check that time_t can represent 2**32 - 1 correctly.  */
+  #define LARGE_TIME_T \\
+    ((time_t) (((time_t) 1 << 30) - 1 + 3 * ((time_t) 1 << 30)))
+  int verify_time_t_range[(LARGE_TIME_T / 65537 == 65535
+                           && LARGE_TIME_T % 65537 == 0)
+                          ? 1 : -1];
+]])
+
+# _AC_SYS_YEAR2038_OPTIONS
+# ------------------------
+# List of known ways to enable support for large time_t.  If you change
+# this list you probably also need to change the AS_CASE at the end of
+# _AC_SYS_YEAR2038_PROBE.
+m4_define([_AC_SYS_YEAR2038_OPTIONS], m4_normalize(
+    ["none needed"]                   dnl 64-bit and newer 32-bit Unix
+    ["-D_TIME_BITS=64"]               dnl glibc 2.34 with some 32-bit ABIs
+    ["-D__MINGW_USE_VC2005_COMPAT"]   dnl 32-bit MinGW
+    ["-U_USE_32_BIT_TIME_T -D__MINGW_USE_VC2005_COMPAT"]
+                                      dnl 32-bit MinGW (misconfiguration)
+))
+
+# _AC_SYS_YEAR2038_PROBE([IF-NOT-DETECTED])
+# -----------------------------------------
+# Subroutine of AC_SYS_YEAR2038.  Probe for time_t that can represent
+# time points more than 2**31 - 1 seconds after the epoch (dates after
+# 2038-01-18, see above) and set the cache variable ac_cv_sys_year2038_opts
+# to one of the values in the _AC_SYS_YEAR2038_OPTIONS list, or to
+# "support not detected" if none of them worked.  Then, set compilation
+# options and #defines as necessary to enable large time_t support.
+#
+# Note that we do not test whether mktime, localtime, etc. handle
+# large values of time_t correctly, as that would require use of
+# AC_TRY_RUN.  Note also that some systems only support large time_t
+# together with large off_t.
+#
+# If support is not detected, the behavior depends on which of the
+# top-level AC_SYS_YEAR2038 macros was used (see below).
+#
+# If you change this macro you may also need to change
+# _AC_SYS_YEAR2038_OPTIONS.
+AC_DEFUN([_AC_SYS_YEAR2038_PROBE],
+[AC_CACHE_CHECK([for $CC option to enable timestamps after Jan 2038],
+  [ac_cv_sys_year2038_opts],
+  [ac_save_CPPFLAGS="$CPPFLAGS"
+  ac_opt_found=no
+  for ac_opt in _AC_SYS_YEAR2038_OPTIONS; do
+    AS_IF([test x"$ac_opt" != x"none needed"],
+      [CPPFLAGS="$ac_save_CPPFLAGS $ac_opt"])
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([_AC_SYS_YEAR2038_TEST_CODE])],
+      [ac_cv_sys_year2038_opts="$ac_opt"
+      ac_opt_found=yes])
+    test $ac_opt_found = no || break
+  done
+  CPPFLAGS="$ac_save_CPPFLAGS"
+  test $ac_opt_found = yes || ac_cv_sys_year2038_opts="support not detected"])
+
+ac_have_year2038=yes
+AS_CASE([$ac_cv_sys_year2038_opts],
+  ["none needed"], [],
+  ["support not detected"],
+    [ac_have_year2038=no
+     AS_CASE([$enable_year2038],
+      [yes],
+        [# If we're not cross compiling and 'touch' works with a large
+        # timestamp, then we can presume the system supports wider time_t
+        # *somehow* and we just weren't able to detect it.  One common
+        # case that we deliberately *don't* probe for is a system that
+        # supports both 32- and 64-bit ABIs but only the 64-bit ABI offers
+        # wide time_t.  (It would be inappropriate for us to override an
+        # intentional use of -m32.)  Error out, demanding use of
+        # --disable-year2038 if this is intentional.
+        AS_IF([test $cross_compiling = no],
+          [AS_IF([TZ=UTC0 touch -t 210602070628.15 conftest.time 2>/dev/null],
+            [AS_CASE([`TZ=UTC0 LC_ALL=C ls -l conftest.time 2>/dev/null`],
+              [*'Feb  7  2106'* | *'Feb  7 17:10'*],
+              [AC_MSG_FAILURE(m4_text_wrap(
+      [this system appears to support timestamps after January 2038,
+       but no mechanism for enabling wide 'time_t' was detected.
+       Did you mean to build a 64-bit binary? (e.g. 'CC="${CC} -m64"'.)
+       To proceed with 32-bit time_t, configure with '--disable-year2038'.],
+      [], [], [55]))])])])])],
+
+  ["-D_TIME_BITS=64"],
+    [AC_DEFINE([_TIME_BITS], [64],
+      [Number of bits in time_t, on hosts where this is settable.])],
+
+  ["-D__MINGW_USE_VC2005_COMPAT=1"],
+    [AC_DEFINE([__MINGW_USE_VC2005_COMPAT], [1],
+      [Define to 1 on platforms where this makes time_t a 64-bit type.])],
+
+  ["-U_USE_32_BIT_TIME_T"*],
+    [AC_MSG_FAILURE(m4_text_wrap(
+      [the 'time_t' type is currently forced to be 32-bit.
+       It will stop working after January 2038.
+       Remove _USE_32BIT_TIME_T from the compiler flags.],
+      [], [], [55]))],
+
+  [AC_MSG_ERROR(
+    [internal error: bad value for \$ac_cv_sys_year2038_opts])])
+])
+
+# _AC_SYS_YEAR2038_ENABLE
+# -----------------------
+# Subroutine of AC_SYS_YEAR2038 and _AC_SYS_YEAR2038_OPT_IN.
+# Depending on which of the YEAR2038 macros was used, add either an
+# --enable-year2038, or a --disable-year2038, or no option at all to
+# the configure script.  Note that this is expanded very late and
+# therefore there cannot be any code in the AC_ARG_ENABLE.  The
+# default value for enable_year2038 is emitted unconditionally
+# because the generated code always looks at this variable.
+m4_define([_AC_SYS_YEAR2038_ENABLE],
+[m4_divert_text([DEFAULTS],
+  m4_provide_if([AC_SYS_YEAR2038],
+    [enable_year2038=yes],
+    [enable_year2038=no]))]dnl
+[AC_ARG_ENABLE([year2038],
+  m4_provide_if([AC_SYS_YEAR2038],
+    [AS_HELP_STRING([--disable-year2038],
+      [do not support timestamps after 2038])],
+    [AS_HELP_STRING([--enable-year2038],
+      [support timestamps after 2038])]))])
+
+# _AC_SYS_YEAR2038_OPT_IN
+# -----------------------
+# If the --enable-year2038 option is given to configure, attempt to
+# detect and activate support for large time_t on 32-bit systems.
+# This macro is automatically invoked by AC_SYS_LARGEFILE when large
+# *file* support is detected.  It does not AC_REQUIRE AC_SYS_LARGEFILE
+# to avoid a dependency loop, and is therefore unsafe to expose as a
+# documented macro.
+AC_DEFUN([_AC_SYS_YEAR2038_OPT_IN],
+[m4_provide_if([_AC_SYS_YEAR2038_PROBE], [], [dnl
+  AS_IF([test "$enable_year2038" != no], [_AC_SYS_YEAR2038_PROBE])
+  AC_CONFIG_COMMANDS_PRE([_AC_SYS_YEAR2038_ENABLE])
+])])
+
+# AC_SYS_YEAR2038
+# ---------------
+# Attempt to detect and activate support for large time_t.
+# On systems where time_t is not always 64 bits, this probe can be
+# skipped by passing the --disable-year2038 option to configure.
+AC_DEFUN([AC_SYS_YEAR2038],
+[AC_REQUIRE([AC_SYS_LARGEFILE])]dnl
+[m4_provide_if([_AC_SYS_YEAR2038_PROBE], [], [dnl
+  AS_IF([test "$enable_year2038" != no], [_AC_SYS_YEAR2038_PROBE])
+  AC_CONFIG_COMMANDS_PRE([_AC_SYS_YEAR2038_ENABLE])
+])])
+
+# _AC_SYS_LARGEFILE_TEST_CODE
+# ---------------------------
+# C code used to probe for large file support.
+m4_define([_AC_SYS_LARGEFILE_TEST_CODE],
+[@%:@include <sys/types.h>
+ /* Check that off_t can represent 2**63 - 1 correctly.
+    We can't simply define LARGE_OFF_T to be 9223372036854775807,
+    since some C++ compilers masquerading as C compilers
+    incorrectly reject 9223372036854775807.  */
+@%:@define LARGE_OFF_T (((off_t) 1 << 31 << 31) - 1 + ((off_t) 1 << 31 << 31))
+  int off_t_is_large[[(LARGE_OFF_T % 2147483629 == 721
+                       && LARGE_OFF_T % 2147483647 == 1)
+                      ? 1 : -1]];[]dnl
+])
+
+# _AC_SYS_LARGEFILE_OPTIONS
+# -------------------------
+# List of known ways to enable support for large files.  If you change
+# this list you probably also need to change the AS_CASE at the end of
+# _AC_SYS_LARGEFILE_PROBE.
+m4_define([_AC_SYS_LARGEFILE_OPTIONS], m4_normalize(
+    ["none needed"]                   dnl Most current systems
+    ["-D_FILE_OFFSET_BITS=64"]        dnl X/Open LFS spec
+    ["-D_LARGE_FILES=1"]              dnl AIX (which versions?)
+    ["-n32"]                          dnl Irix 6.2 w/ SGI compiler
+))
+
+# _AC_SYS_LARGEFILE_PROBE
+# -----------------------
+# Subroutine of AC_SYS_LARGEFILE. Probe for large file support and set
+# the cache variable ac_cv_sys_largefile_opts to one of the values in
+# the _AC_SYS_LARGEFILE_OPTIONS list, or to "support not detected" if
+# none of the options in that list worked.  Then, set compilation
+# options and #defines as necessary to enable large file support.
+#
+# If large file support is not detected, the behavior depends on which of
+# the top-level AC_SYS_LARGEFILE macros was used (see below).
+#
+# If you change this macro you may also need to change
+# _AC_SYS_LARGEFILE_OPTIONS.
+AC_DEFUN([_AC_SYS_LARGEFILE_PROBE],
+[AC_CACHE_CHECK([for $CC option to enable large file support],
+  [ac_cv_sys_largefile_opts],
+  [ac_save_CC="$CC"
+  ac_opt_found=no
+  for ac_opt in _AC_SYS_LARGEFILE_OPTIONS; do
+    AS_IF([test x"$ac_opt" != x"none needed"],
+      [CC="$ac_save_CC $ac_opt"])
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([_AC_SYS_LARGEFILE_TEST_CODE])],
+      [ac_cv_sys_largefile_opts="$ac_opt"
+      ac_opt_found=yes])
+    test $ac_opt_found = no || break
+  done
+  CC="$ac_save_CC"
+  test $ac_opt_found = yes || ac_cv_sys_largefile_opts="support not detected"])
+
+ac_have_largefile=yes
+AS_CASE([$ac_cv_sys_largefile_opts],
+  ["none needed"], [],
+  ["support not detected"],
+    [ac_have_largefile=no],
+
+  ["-D_FILE_OFFSET_BITS=64"],
+    [AC_DEFINE([_FILE_OFFSET_BITS], [64],
+      [Number of bits in a file offset, on hosts where this is settable.])],
+
+  ["-D_LARGE_FILES=1"],
+    [AC_DEFINE([_LARGE_FILES], [1],
+      [Define to 1 on platforms where this makes off_t a 64-bit type.])],
 
+  ["-n32"],
+    [CC="$CC -n32"],
 
-# _AC_SYS_LARGEFILE_MACRO_VALUE(C-MACRO, VALUE,
-#                               CACHE-VAR,
-#                               DESCRIPTION,
-#                               PROLOGUE, [FUNCTION-BODY])
-# --------------------------------------------------------
-m4_define([_AC_SYS_LARGEFILE_MACRO_VALUE],
-[AC_CACHE_CHECK([for $1 value needed for large files], [$3],
-[while :; do
-  m4_ifval([$6], [AC_LINK_IFELSE], [AC_COMPILE_IFELSE])(
-    [AC_LANG_PROGRAM([$5], [$6])],
-    [$3=no; break])
-  m4_ifval([$6], [AC_LINK_IFELSE], [AC_COMPILE_IFELSE])(
-    [AC_LANG_PROGRAM([@%:@define $1 $2
-$5], [$6])],
-    [$3=$2; break])
-  $3=unknown
-  break
-done])
-case $$3 in #(
-  no | unknown) ;;
-  *) AC_DEFINE_UNQUOTED([$1], [$$3], [$4]);;
-esac
-rm -rf conftest*[]dnl
-])# _AC_SYS_LARGEFILE_MACRO_VALUE
+  [AC_MSG_ERROR(
+    [internal error: bad value for \$ac_cv_sys_largefile_opts])])
 
+_AC_SYS_YEAR2038_OPT_IN
+])
+
+# _AC_SYS_LARGEFILE_ENABLE
+# ------------------------
+# Subroutine of AC_SYS_LARGEFILE.  Note that this
+# is expanded very late and therefore there cannot be any code in the
+# AC_ARG_ENABLE.  The default value for enable_largefile is emitted
+# unconditionally because the generated shell code always looks at
+# this variable.
+m4_define([_AC_SYS_LARGEFILE_ENABLE],
+[m4_divert_text([DEFAULTS],
+  enable_largefile=yes)]dnl
+[AC_ARG_ENABLE([largefile],
+  [AS_HELP_STRING([--disable-largefile], [omit support for large files])])])
 
 # AC_SYS_LARGEFILE
 # ----------------
 # By default, many hosts won't let programs access large files;
 # one must use special compiler options to get large-file access to work.
 # For more details about this brain damage please see:
-# http://www.unix-systems.org/version2/whatsnew/lfs20mar.html
+# http://www.unix.org/version2/whatsnew/lfs20mar.html
+# Additionally, on Linux file systems with 64-bit inodes a file that happens
+# to have a 64-bit inode number cannot be accessed by 32-bit applications on
+# Linux x86/x86_64.  This can occur with file systems such as XFS and NFS.
+# This macro allows configuration to continue if the system doesn't support
+# large files.
 AC_DEFUN([AC_SYS_LARGEFILE],
-[AC_ARG_ENABLE(largefile,
-               [  --disable-largefile     omit support for large files])
-if test "$enable_largefile" != no; then
-
-  AC_CACHE_CHECK([for special C compiler options needed for large files],
-    ac_cv_sys_largefile_CC,
-    [ac_cv_sys_largefile_CC=no
-     if test "$GCC" != yes; then
-       ac_save_CC=$CC
-       while :; do
-         # IRIX 6.2 and later do not support large files by default,
-         # so use the C compiler's -n32 option if that helps.
-         AC_LANG_CONFTEST([AC_LANG_PROGRAM([_AC_SYS_LARGEFILE_TEST_INCLUDES])])
-         AC_COMPILE_IFELSE([], [break])
-         CC="$CC -n32"
-         AC_COMPILE_IFELSE([], [ac_cv_sys_largefile_CC=' -n32'; break])
-         break
-       done
-       CC=$ac_save_CC
-       rm -f conftest.$ac_ext
-    fi])
-  if test "$ac_cv_sys_largefile_CC" != no; then
-    CC=$CC$ac_cv_sys_largefile_CC
-  fi
-
-  _AC_SYS_LARGEFILE_MACRO_VALUE(_FILE_OFFSET_BITS, 64,
-    ac_cv_sys_file_offset_bits,
-    [Number of bits in a file offset, on hosts where this is settable.],
-    [_AC_SYS_LARGEFILE_TEST_INCLUDES])
-  if test $ac_cv_sys_file_offset_bits = unknown; then
-    _AC_SYS_LARGEFILE_MACRO_VALUE(_LARGE_FILES, 1,
-      ac_cv_sys_large_files,
-      [Define for large files, on AIX-style hosts.],
-      [_AC_SYS_LARGEFILE_TEST_INCLUDES])
-  fi
-
-  AC_DEFINE([_DARWIN_USE_64_BIT_INODE], [1],
-    [Enable large inode numbers on Mac OS X 10.5.])
-fi
-])# AC_SYS_LARGEFILE
-])# m4_version_prereq 2.70
+[m4_provide_if([_AC_SYS_LARGEFILE_PROBE], [], [dnl
+  AS_IF([test "$enable_largefile" != no], [_AC_SYS_LARGEFILE_PROBE])
+  AC_CONFIG_COMMANDS_PRE([_AC_SYS_LARGEFILE_ENABLE])
+])])
+])# m4_ifndef AC_SYS_YEAR2038
 
 # Enable large files on systems where this is implemented by Gnulib, not by the
 # system headers.
@@ -126,9 +341,24 @@ AC_DEFUN([gl_LARGEFILE],
       else
         WINDOWS_64_BIT_OFF_T=0
       fi
-      dnl But all native Windows platforms (including mingw64) have a 32-bit
-      dnl st_size member in 'struct stat'.
-      WINDOWS_64_BIT_ST_SIZE=1
+      dnl Some mingw versions define, if _FILE_OFFSET_BITS=64, 'struct stat'
+      dnl to 'struct _stat32i64' or 'struct _stat64' (depending on
+      dnl _USE_32BIT_TIME_T), which has a 32-bit st_size member.
+      AC_CACHE_CHECK([for 64-bit st_size], [gl_cv_member_st_size_64],
+        [AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM(
+              [[#include <sys/types.h>
+                struct stat buf;
+                int verify_st_size_size[sizeof (buf.st_size) >= 8 ? 1 : -1];
+              ]],
+              [[]])],
+           [gl_cv_member_st_size_64=yes], [gl_cv_member_st_size_64=no])
+        ])
+      if test $gl_cv_member_st_size_64 = no; then
+        WINDOWS_64_BIT_ST_SIZE=1
+      else
+        WINDOWS_64_BIT_ST_SIZE=0
+      fi
       ;;
     *)
       dnl Nothing to do on gnulib's side.
diff --git a/gl/m4/lcmessage.m4 b/gl/m4/lcmessage.m4
deleted file mode 100644
index d62a175f..00000000
--- a/gl/m4/lcmessage.m4
+++ /dev/null
@@ -1,35 +0,0 @@
-# lcmessage.m4 serial 7 (gettext-0.18.2)
-dnl Copyright (C) 1995-2002, 2004-2005, 2008-2013 Free Software Foundation,
-dnl Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-dnl
-dnl This file can can be used in projects which are not available under
-dnl the GNU General Public License or the GNU Library General Public
-dnl License but which still want to provide support for the GNU gettext
-dnl functionality.
-dnl Please note that the actual code of the GNU gettext library is covered
-dnl by the GNU Library General Public License, and the rest of the GNU
-dnl gettext package package is covered by the GNU General Public License.
-dnl They are *not* in the public domain.
-
-dnl Authors:
-dnl   Ulrich Drepper <drepper@cygnus.com>, 1995.
-
-# Check whether LC_MESSAGES is available in <locale.h>.
-
-AC_DEFUN([gt_LC_MESSAGES],
-[
-  AC_CACHE_CHECK([for LC_MESSAGES], [gt_cv_val_LC_MESSAGES],
-    [AC_LINK_IFELSE(
-       [AC_LANG_PROGRAM(
-          [[#include <locale.h>]],
-          [[return LC_MESSAGES]])],
-       [gt_cv_val_LC_MESSAGES=yes],
-       [gt_cv_val_LC_MESSAGES=no])])
-  if test $gt_cv_val_LC_MESSAGES = yes; then
-    AC_DEFINE([HAVE_LC_MESSAGES], [1],
-      [Define if your <locale.h> file defines LC_MESSAGES.])
-  fi
-])
diff --git a/gl/m4/lib-ld.m4 b/gl/m4/lib-ld.m4
index c145e478..6bc1886f 100644
--- a/gl/m4/lib-ld.m4
+++ b/gl/m4/lib-ld.m4
@@ -1,5 +1,5 @@
-# lib-ld.m4 serial 6
-dnl Copyright (C) 1996-2003, 2009-2013 Free Software Foundation, Inc.
+# lib-ld.m4 serial 10
+dnl Copyright (C) 1996-2003, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -47,73 +47,122 @@ if test "${PATH_SEPARATOR+set}" != set; then
        }
 fi
 
-ac_prog=ld
-if test "$GCC" = yes; then
-  # Check if gcc -print-prog-name=ld gives a path.
+if test -n "$LD"; then
+  AC_MSG_CHECKING([for ld])
+elif test "$GCC" = yes; then
   AC_MSG_CHECKING([for ld used by $CC])
-  case $host in
-  *-*-mingw*)
-    # gcc leaves a trailing carriage return which upsets mingw
-    ac_prog=`($CC -print-prog-name=ld) 2>&5 | tr -d '\015'` ;;
-  *)
-    ac_prog=`($CC -print-prog-name=ld) 2>&5` ;;
-  esac
-  case $ac_prog in
-    # Accept absolute paths.
-    [[\\/]]* | ?:[[\\/]]*)
-      re_direlt='/[[^/]][[^/]]*/\.\./'
-      # Canonicalize the pathname of ld
-      ac_prog=`echo "$ac_prog"| sed 's%\\\\%/%g'`
-      while echo "$ac_prog" | grep "$re_direlt" > /dev/null 2>&1; do
-        ac_prog=`echo $ac_prog| sed "s%$re_direlt%/%"`
-      done
-      test -z "$LD" && LD="$ac_prog"
-      ;;
-  "")
-    # If it fails, then pretend we aren't using GCC.
-    ac_prog=ld
-    ;;
-  *)
-    # If it is relative, then search for the first ld in PATH.
-    with_gnu_ld=unknown
-    ;;
-  esac
 elif test "$with_gnu_ld" = yes; then
   AC_MSG_CHECKING([for GNU ld])
 else
   AC_MSG_CHECKING([for non-GNU ld])
 fi
-AC_CACHE_VAL([acl_cv_path_LD],
-[if test -z "$LD"; then
-  acl_save_ifs="$IFS"; IFS=$PATH_SEPARATOR
-  for ac_dir in $PATH; do
-    IFS="$acl_save_ifs"
-    test -z "$ac_dir" && ac_dir=.
-    if test -f "$ac_dir/$ac_prog" || test -f "$ac_dir/$ac_prog$ac_exeext"; then
-      acl_cv_path_LD="$ac_dir/$ac_prog"
-      # Check to see if the program is GNU ld.  I'd rather use --version,
-      # but apparently some variants of GNU ld only accept -v.
-      # Break only if it was the GNU/non-GNU ld that we prefer.
-      case `"$acl_cv_path_LD" -v 2>&1 </dev/null` in
-      *GNU* | *'with BFD'*)
-        test "$with_gnu_ld" != no && break
-        ;;
-      *)
-        test "$with_gnu_ld" != yes && break
-        ;;
+if test -n "$LD"; then
+  # Let the user override the test with a path.
+  :
+else
+  AC_CACHE_VAL([acl_cv_path_LD],
+  [
+    acl_cv_path_LD= # Final result of this test
+    ac_prog=ld # Program to search in $PATH
+    if test "$GCC" = yes; then
+      # Check if gcc -print-prog-name=ld gives a path.
+      case $host in
+        *-*-mingw*)
+          # gcc leaves a trailing carriage return which upsets mingw
+          acl_output=`($CC -print-prog-name=ld) 2>&5 | tr -d '\015'` ;;
+        *)
+          acl_output=`($CC -print-prog-name=ld) 2>&5` ;;
+      esac
+      case $acl_output in
+        # Accept absolute paths.
+        [[\\/]]* | ?:[[\\/]]*)
+          re_direlt='/[[^/]][[^/]]*/\.\./'
+          # Canonicalize the pathname of ld
+          acl_output=`echo "$acl_output" | sed 's%\\\\%/%g'`
+          while echo "$acl_output" | grep "$re_direlt" > /dev/null 2>&1; do
+            acl_output=`echo $acl_output | sed "s%$re_direlt%/%"`
+          done
+          # Got the pathname. No search in PATH is needed.
+          acl_cv_path_LD="$acl_output"
+          ac_prog=
+          ;;
+        "")
+          # If it fails, then pretend we aren't using GCC.
+          ;;
+        *)
+          # If it is relative, then search for the first ld in PATH.
+          with_gnu_ld=unknown
+          ;;
       esac
     fi
-  done
-  IFS="$acl_save_ifs"
-else
-  acl_cv_path_LD="$LD" # Let the user override the test with a path.
-fi])
-LD="$acl_cv_path_LD"
+    if test -n "$ac_prog"; then
+      # Search for $ac_prog in $PATH.
+      acl_save_ifs="$IFS"; IFS=$PATH_SEPARATOR
+      for ac_dir in $PATH; do
+        IFS="$acl_save_ifs"
+        test -z "$ac_dir" && ac_dir=.
+        if test -f "$ac_dir/$ac_prog" || test -f "$ac_dir/$ac_prog$ac_exeext"; then
+          acl_cv_path_LD="$ac_dir/$ac_prog"
+          # Check to see if the program is GNU ld.  I'd rather use --version,
+          # but apparently some variants of GNU ld only accept -v.
+          # Break only if it was the GNU/non-GNU ld that we prefer.
+          case `"$acl_cv_path_LD" -v 2>&1 </dev/null` in
+            *GNU* | *'with BFD'*)
+              test "$with_gnu_ld" != no && break
+              ;;
+            *)
+              test "$with_gnu_ld" != yes && break
+              ;;
+          esac
+        fi
+      done
+      IFS="$acl_save_ifs"
+    fi
+    case $host in
+      *-*-aix*)
+        AC_COMPILE_IFELSE(
+          [AC_LANG_SOURCE(
+             [[#if defined __powerpc64__ || defined __LP64__
+                int ok;
+               #else
+                error fail
+               #endif
+             ]])],
+          [# The compiler produces 64-bit code. Add option '-b64' so that the
+           # linker groks 64-bit object files.
+           case "$acl_cv_path_LD " in
+             *" -b64 "*) ;;
+             *) acl_cv_path_LD="$acl_cv_path_LD -b64" ;;
+           esac
+          ], [])
+        ;;
+      sparc64-*-netbsd*)
+        AC_COMPILE_IFELSE(
+          [AC_LANG_SOURCE(
+             [[#if defined __sparcv9 || defined __arch64__
+                int ok;
+               #else
+                error fail
+               #endif
+             ]])],
+          [],
+          [# The compiler produces 32-bit code. Add option '-m elf32_sparc'
+           # so that the linker groks 32-bit object files.
+           case "$acl_cv_path_LD " in
+             *" -m elf32_sparc "*) ;;
+             *) acl_cv_path_LD="$acl_cv_path_LD -m elf32_sparc" ;;
+           esac
+          ])
+        ;;
+    esac
+  ])
+  LD="$acl_cv_path_LD"
+fi
 if test -n "$LD"; then
   AC_MSG_RESULT([$LD])
 else
   AC_MSG_RESULT([no])
+  AC_MSG_ERROR([no acceptable ld found in \$PATH])
 fi
-test -z "$LD" && AC_MSG_ERROR([no acceptable ld found in \$PATH])
 AC_LIB_PROG_LD_GNU
 ])
diff --git a/gl/m4/lib-link.m4 b/gl/m4/lib-link.m4
index 073f0405..653e34f8 100644
--- a/gl/m4/lib-link.m4
+++ b/gl/m4/lib-link.m4
@@ -1,12 +1,12 @@
-# lib-link.m4 serial 26 (gettext-0.18.2)
-dnl Copyright (C) 2001-2013 Free Software Foundation, Inc.
+# lib-link.m4 serial 33
+dnl Copyright (C) 2001-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl From Bruno Haible.
 
-AC_PREREQ([2.54])
+AC_PREREQ([2.61])
 
 dnl AC_LIB_LINKFLAGS(name [, dependencies]) searches for libname and
 dnl the libraries corresponding to explicit and implicit dependencies.
@@ -124,8 +124,8 @@ dnl   acl_hardcode_direct,
 dnl   acl_hardcode_minus_L.
 AC_DEFUN([AC_LIB_RPATH],
 [
-  dnl Tell automake >= 1.10 to complain if config.rpath is missing.
-  m4_ifdef([AC_REQUIRE_AUX_FILE], [AC_REQUIRE_AUX_FILE([config.rpath])])
+  dnl Complain if config.rpath is missing.
+  AC_REQUIRE_AUX_FILE([config.rpath])
   AC_REQUIRE([AC_PROG_CC])                dnl we use $CC, $GCC, $LDFLAGS
   AC_REQUIRE([AC_LIB_PROG_LD])            dnl we use $LD, $with_gnu_ld
   AC_REQUIRE([AC_CANONICAL_HOST])         dnl we use $host
@@ -187,17 +187,17 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
   pushdef([PACKUP],[m4_translit(PACK,[abcdefghijklmnopqrstuvwxyz./+-],
                                      [ABCDEFGHIJKLMNOPQRSTUVWXYZ____])])
   pushdef([PACKLIBS],[m4_ifdef([acl_frompackage_]NAME, [acl_libsinpackage_]PACKUP, lib[$1])])
-  dnl Autoconf >= 2.61 supports dots in --with options.
-  pushdef([P_A_C_K],[m4_if(m4_version_compare(m4_defn([m4_PACKAGE_VERSION]),[2.61]),[-1],[m4_translit(PACK,[.],[_])],PACK)])
   dnl By default, look in $includedir and $libdir.
   use_additional=yes
   AC_LIB_WITH_FINAL_PREFIX([
     eval additional_includedir=\"$includedir\"
     eval additional_libdir=\"$libdir\"
+    eval additional_libdir2=\"$exec_prefix/$acl_libdirstem2\"
+    eval additional_libdir3=\"$exec_prefix/$acl_libdirstem3\"
   ])
-  AC_ARG_WITH(P_A_C_K[-prefix],
-[[  --with-]]P_A_C_K[[-prefix[=DIR]  search for ]PACKLIBS[ in DIR/include and DIR/lib
-  --without-]]P_A_C_K[[-prefix     don't search for ]PACKLIBS[ in includedir and libdir]],
+  AC_ARG_WITH(PACK[-prefix],
+[[  --with-]]PACK[[-prefix[=DIR]  search for ]]PACKLIBS[[ in DIR/include and DIR/lib
+  --without-]]PACK[[-prefix     don't search for ]]PACKLIBS[[ in includedir and libdir]],
 [
     if test "X$withval" = "Xno"; then
       use_additional=no
@@ -206,17 +206,23 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
         AC_LIB_WITH_FINAL_PREFIX([
           eval additional_includedir=\"$includedir\"
           eval additional_libdir=\"$libdir\"
+          eval additional_libdir2=\"$exec_prefix/$acl_libdirstem2\"
+          eval additional_libdir3=\"$exec_prefix/$acl_libdirstem3\"
         ])
       else
         additional_includedir="$withval/include"
         additional_libdir="$withval/$acl_libdirstem"
-        if test "$acl_libdirstem2" != "$acl_libdirstem" \
-           && ! test -d "$withval/$acl_libdirstem"; then
-          additional_libdir="$withval/$acl_libdirstem2"
-        fi
+        additional_libdir2="$withval/$acl_libdirstem2"
+        additional_libdir3="$withval/$acl_libdirstem3"
       fi
     fi
 ])
+  if test "X$additional_libdir2" = "X$additional_libdir"; then
+    additional_libdir2=
+  fi
+  if test "X$additional_libdir3" = "X$additional_libdir"; then
+    additional_libdir3=
+  fi
   dnl Search the library and its dependencies in $additional_libdir and
   dnl $LDFLAGS. Using breadth-first-seach.
   LIB[]NAME=
@@ -272,48 +278,54 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
             shrext=
           fi
           if test $use_additional = yes; then
-            dir="$additional_libdir"
-            dnl The same code as in the loop below:
-            dnl First look for a shared library.
-            if test -n "$acl_shlibext"; then
-              if test -f "$dir/$libname$shrext"; then
-                found_dir="$dir"
-                found_so="$dir/$libname$shrext"
-              else
-                if test "$acl_library_names_spec" = '$libname$shrext$versuffix'; then
-                  ver=`(cd "$dir" && \
-                        for f in "$libname$shrext".*; do echo "$f"; done \
-                        | sed -e "s,^$libname$shrext\\\\.,," \
-                        | sort -t '.' -n -r -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 \
-                        | sed 1q ) 2>/dev/null`
-                  if test -n "$ver" && test -f "$dir/$libname$shrext.$ver"; then
-                    found_dir="$dir"
-                    found_so="$dir/$libname$shrext.$ver"
+            for additional_libdir_variable in additional_libdir additional_libdir2 additional_libdir3; do
+              if test "X$found_dir" = "X"; then
+                eval dir=\$$additional_libdir_variable
+                if test -n "$dir"; then
+                  dnl The same code as in the loop below:
+                  dnl First look for a shared library.
+                  if test -n "$acl_shlibext"; then
+                    if test -f "$dir/$libname$shrext" && acl_is_expected_elfclass < "$dir/$libname$shrext"; then
+                      found_dir="$dir"
+                      found_so="$dir/$libname$shrext"
+                    else
+                      if test "$acl_library_names_spec" = '$libname$shrext$versuffix'; then
+                        ver=`(cd "$dir" && \
+                              for f in "$libname$shrext".*; do echo "$f"; done \
+                              | sed -e "s,^$libname$shrext\\\\.,," \
+                              | sort -t '.' -n -r -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 \
+                              | sed 1q ) 2>/dev/null`
+                        if test -n "$ver" && test -f "$dir/$libname$shrext.$ver" && acl_is_expected_elfclass < "$dir/$libname$shrext.$ver"; then
+                          found_dir="$dir"
+                          found_so="$dir/$libname$shrext.$ver"
+                        fi
+                      else
+                        eval library_names=\"$acl_library_names_spec\"
+                        for f in $library_names; do
+                          if test -f "$dir/$f" && acl_is_expected_elfclass < "$dir/$f"; then
+                            found_dir="$dir"
+                            found_so="$dir/$f"
+                            break
+                          fi
+                        done
+                      fi
+                    fi
                   fi
-                else
-                  eval library_names=\"$acl_library_names_spec\"
-                  for f in $library_names; do
-                    if test -f "$dir/$f"; then
+                  dnl Then look for a static library.
+                  if test "X$found_dir" = "X"; then
+                    if test -f "$dir/$libname.$acl_libext" && ${AR-ar} -p "$dir/$libname.$acl_libext" | acl_is_expected_elfclass; then
                       found_dir="$dir"
-                      found_so="$dir/$f"
-                      break
+                      found_a="$dir/$libname.$acl_libext"
                     fi
-                  done
+                  fi
+                  if test "X$found_dir" != "X"; then
+                    if test -f "$dir/$libname.la"; then
+                      found_la="$dir/$libname.la"
+                    fi
+                  fi
                 fi
               fi
-            fi
-            dnl Then look for a static library.
-            if test "X$found_dir" = "X"; then
-              if test -f "$dir/$libname.$acl_libext"; then
-                found_dir="$dir"
-                found_a="$dir/$libname.$acl_libext"
-              fi
-            fi
-            if test "X$found_dir" != "X"; then
-              if test -f "$dir/$libname.la"; then
-                found_la="$dir/$libname.la"
-              fi
-            fi
+            done
           fi
           if test "X$found_dir" = "X"; then
             for x in $LDFLAGS $LTLIB[]NAME; do
@@ -323,7 +335,7 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
                   dir=`echo "X$x" | sed -e 's/^X-L//'`
                   dnl First look for a shared library.
                   if test -n "$acl_shlibext"; then
-                    if test -f "$dir/$libname$shrext"; then
+                    if test -f "$dir/$libname$shrext" && acl_is_expected_elfclass < "$dir/$libname$shrext"; then
                       found_dir="$dir"
                       found_so="$dir/$libname$shrext"
                     else
@@ -333,14 +345,14 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
                               | sed -e "s,^$libname$shrext\\\\.,," \
                               | sort -t '.' -n -r -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 \
                               | sed 1q ) 2>/dev/null`
-                        if test -n "$ver" && test -f "$dir/$libname$shrext.$ver"; then
+                        if test -n "$ver" && test -f "$dir/$libname$shrext.$ver" && acl_is_expected_elfclass < "$dir/$libname$shrext.$ver"; then
                           found_dir="$dir"
                           found_so="$dir/$libname$shrext.$ver"
                         fi
                       else
                         eval library_names=\"$acl_library_names_spec\"
                         for f in $library_names; do
-                          if test -f "$dir/$f"; then
+                          if test -f "$dir/$f" && acl_is_expected_elfclass < "$dir/$f"; then
                             found_dir="$dir"
                             found_so="$dir/$f"
                             break
@@ -351,7 +363,7 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
                   fi
                   dnl Then look for a static library.
                   if test "X$found_dir" = "X"; then
-                    if test -f "$dir/$libname.$acl_libext"; then
+                    if test -f "$dir/$libname.$acl_libext" && ${AR-ar} -p "$dir/$libname.$acl_libext" | acl_is_expected_elfclass; then
                       found_dir="$dir"
                       found_a="$dir/$libname.$acl_libext"
                     fi
@@ -377,7 +389,8 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
               dnl standard /usr/lib.
               if test "$enable_rpath" = no \
                  || test "X$found_dir" = "X/usr/$acl_libdirstem" \
-                 || test "X$found_dir" = "X/usr/$acl_libdirstem2"; then
+                 || test "X$found_dir" = "X/usr/$acl_libdirstem2" \
+                 || test "X$found_dir" = "X/usr/$acl_libdirstem3"; then
                 dnl No hardcoding is needed.
                 LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }$found_so"
               else
@@ -477,6 +490,13 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
                 fi
                 additional_includedir="$basedir/include"
                 ;;
+              */$acl_libdirstem3 | */$acl_libdirstem3/)
+                basedir=`echo "X$found_dir" | sed -e 's,^X,,' -e "s,/$acl_libdirstem3/"'*$,,'`
+                if test "$name" = '$1'; then
+                  LIB[]NAME[]_PREFIX="$basedir"
+                fi
+                additional_includedir="$basedir/include"
+                ;;
             esac
             if test "X$additional_includedir" != "X"; then
               dnl Potentially add $additional_includedir to $INCNAME.
@@ -527,19 +547,21 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
               for dep in $dependency_libs; do
                 case "$dep" in
                   -L*)
-                    additional_libdir=`echo "X$dep" | sed -e 's/^X-L//'`
-                    dnl Potentially add $additional_libdir to $LIBNAME and $LTLIBNAME.
+                    dependency_libdir=`echo "X$dep" | sed -e 's/^X-L//'`
+                    dnl Potentially add $dependency_libdir to $LIBNAME and $LTLIBNAME.
                     dnl But don't add it
                     dnl   1. if it's the standard /usr/lib,
                     dnl   2. if it's /usr/local/lib and we are using GCC on Linux,
                     dnl   3. if it's already present in $LDFLAGS or the already
                     dnl      constructed $LIBNAME,
                     dnl   4. if it doesn't exist as a directory.
-                    if test "X$additional_libdir" != "X/usr/$acl_libdirstem" \
-                       && test "X$additional_libdir" != "X/usr/$acl_libdirstem2"; then
+                    if test "X$dependency_libdir" != "X/usr/$acl_libdirstem" \
+                       && test "X$dependency_libdir" != "X/usr/$acl_libdirstem2" \
+                       && test "X$dependency_libdir" != "X/usr/$acl_libdirstem3"; then
                       haveit=
-                      if test "X$additional_libdir" = "X/usr/local/$acl_libdirstem" \
-                         || test "X$additional_libdir" = "X/usr/local/$acl_libdirstem2"; then
+                      if test "X$dependency_libdir" = "X/usr/local/$acl_libdirstem" \
+                         || test "X$dependency_libdir" = "X/usr/local/$acl_libdirstem2" \
+                         || test "X$dependency_libdir" = "X/usr/local/$acl_libdirstem3"; then
                         if test -n "$GCC"; then
                           case $host_os in
                             linux* | gnu* | k*bsd*-gnu) haveit=yes;;
@@ -550,29 +572,29 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
                         haveit=
                         for x in $LDFLAGS $LIB[]NAME; do
                           AC_LIB_WITH_FINAL_PREFIX([eval x=\"$x\"])
-                          if test "X$x" = "X-L$additional_libdir"; then
+                          if test "X$x" = "X-L$dependency_libdir"; then
                             haveit=yes
                             break
                           fi
                         done
                         if test -z "$haveit"; then
-                          if test -d "$additional_libdir"; then
-                            dnl Really add $additional_libdir to $LIBNAME.
-                            LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }-L$additional_libdir"
+                          if test -d "$dependency_libdir"; then
+                            dnl Really add $dependency_libdir to $LIBNAME.
+                            LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }-L$dependency_libdir"
                           fi
                         fi
                         haveit=
                         for x in $LDFLAGS $LTLIB[]NAME; do
                           AC_LIB_WITH_FINAL_PREFIX([eval x=\"$x\"])
-                          if test "X$x" = "X-L$additional_libdir"; then
+                          if test "X$x" = "X-L$dependency_libdir"; then
                             haveit=yes
                             break
                           fi
                         done
                         if test -z "$haveit"; then
-                          if test -d "$additional_libdir"; then
-                            dnl Really add $additional_libdir to $LTLIBNAME.
-                            LTLIB[]NAME="${LTLIB[]NAME}${LTLIB[]NAME:+ }-L$additional_libdir"
+                          if test -d "$dependency_libdir"; then
+                            dnl Really add $dependency_libdir to $LTLIBNAME.
+                            LTLIB[]NAME="${LTLIB[]NAME}${LTLIB[]NAME:+ }-L$dependency_libdir"
                           fi
                         fi
                       fi
@@ -609,7 +631,20 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
                     ;;
                   -l*)
                     dnl Handle this in the next round.
-                    names_next_round="$names_next_round "`echo "X$dep" | sed -e 's/^X-l//'`
+                    dnl But on GNU systems, ignore -lc options, because
+                    dnl   - linking with libc is the default anyway,
+                    dnl   - linking with libc.a may produce an error
+                    dnl     "/usr/bin/ld: dynamic STT_GNU_IFUNC symbol `strcmp' with pointer equality in `/usr/lib/libc.a(strcmp.o)' can not be used when making an executable; recompile with -fPIE and relink with -pie"
+                    dnl     or may produce an executable that always crashes, see
+                    dnl     <https://lists.gnu.org/archive/html/grep-devel/2020-09/msg00052.html>.
+                    dep=`echo "X$dep" | sed -e 's/^X-l//'`
+                    if test "X$dep" != Xc \
+                       || case $host_os in
+                            linux* | gnu* | k*bsd*-gnu) false ;;
+                            *)                          true ;;
+                          esac; then
+                      names_next_round="$names_next_round $dep"
+                    fi
                     ;;
                   *.la)
                     dnl Handle this in the next round. Throw away the .la's
@@ -670,7 +705,6 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
       LTLIB[]NAME="${LTLIB[]NAME}${LTLIB[]NAME:+ }-R$found_dir"
     done
   fi
-  popdef([P_A_C_K])
   popdef([PACKLIBS])
   popdef([PACKUP])
   popdef([PACK])
@@ -721,7 +755,8 @@ AC_DEFUN([AC_LIB_LINKFLAGS_FROM_LIBS],
           dir="$next"
           dnl No need to hardcode the standard /usr/lib.
           if test "X$dir" != "X/usr/$acl_libdirstem" \
-             && test "X$dir" != "X/usr/$acl_libdirstem2"; then
+             && test "X$dir" != "X/usr/$acl_libdirstem2" \
+             && test "X$dir" != "X/usr/$acl_libdirstem3"; then
             rpathdirs="$rpathdirs $dir"
           fi
           next=
@@ -731,7 +766,8 @@ AC_DEFUN([AC_LIB_LINKFLAGS_FROM_LIBS],
             -L*) dir=`echo "X$opt" | sed -e 's,^X-L,,'`
                  dnl No need to hardcode the standard /usr/lib.
                  if test "X$dir" != "X/usr/$acl_libdirstem" \
-                    && test "X$dir" != "X/usr/$acl_libdirstem2"; then
+                    && test "X$dir" != "X/usr/$acl_libdirstem2" \
+                    && test "X$dir" != "X/usr/$acl_libdirstem3"; then
                    rpathdirs="$rpathdirs $dir"
                  fi
                  next= ;;
diff --git a/gl/m4/lib-prefix.m4 b/gl/m4/lib-prefix.m4
index 60908e8f..aefe7f71 100644
--- a/gl/m4/lib-prefix.m4
+++ b/gl/m4/lib-prefix.m4
@@ -1,18 +1,11 @@
-# lib-prefix.m4 serial 7 (gettext-0.18)
-dnl Copyright (C) 2001-2005, 2008-2013 Free Software Foundation, Inc.
+# lib-prefix.m4 serial 20
+dnl Copyright (C) 2001-2005, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl From Bruno Haible.
 
-dnl AC_LIB_ARG_WITH is synonymous to AC_ARG_WITH in autoconf-2.13, and
-dnl similar to AC_ARG_WITH in autoconf 2.52...2.57 except that is doesn't
-dnl require excessive bracketing.
-ifdef([AC_HELP_STRING],
-[AC_DEFUN([AC_LIB_ARG_WITH], [AC_ARG_WITH([$1],[[$2]],[$3],[$4])])],
-[AC_DEFUN([AC_][LIB_ARG_WITH], [AC_ARG_WITH([$1],[$2],[$3],[$4])])])
-
 dnl AC_LIB_PREFIX adds to the CPPFLAGS and LDFLAGS the flags that are needed
 dnl to access previously installed libraries. The basic assumption is that
 dnl a user will want packages to use other packages he previously installed
@@ -32,9 +25,9 @@ AC_DEFUN([AC_LIB_PREFIX],
     eval additional_includedir=\"$includedir\"
     eval additional_libdir=\"$libdir\"
   ])
-  AC_LIB_ARG_WITH([lib-prefix],
-[  --with-lib-prefix[=DIR] search for libraries in DIR/include and DIR/lib
-  --without-lib-prefix    don't search for libraries in includedir and libdir],
+  AC_ARG_WITH([lib-prefix],
+[[  --with-lib-prefix[=DIR] search for libraries in DIR/include and DIR/lib
+  --without-lib-prefix    don't search for libraries in includedir and libdir]],
 [
     if test "X$withval" = "Xno"; then
       use_additional=no
@@ -154,71 +147,177 @@ AC_DEFUN([AC_LIB_WITH_FINAL_PREFIX],
 ])
 
 dnl AC_LIB_PREPARE_MULTILIB creates
-dnl - a variable acl_libdirstem, containing the basename of the libdir, either
-dnl   "lib" or "lib64" or "lib/64",
-dnl - a variable acl_libdirstem2, as a secondary possible value for
-dnl   acl_libdirstem, either the same as acl_libdirstem or "lib/sparcv9" or
-dnl   "lib/amd64".
+dnl - a function acl_is_expected_elfclass, that tests whether standard input
+dn;   has a 32-bit or 64-bit ELF header, depending on the host CPU ABI,
+dnl - 3 variables acl_libdirstem, acl_libdirstem2, acl_libdirstem3, containing
+dnl   the basename of the libdir to try in turn, either "lib" or "lib64" or
+dnl   "lib/64" or "lib32" or "lib/sparcv9" or "lib/amd64" or similar.
 AC_DEFUN([AC_LIB_PREPARE_MULTILIB],
 [
-  dnl There is no formal standard regarding lib and lib64.
-  dnl On glibc systems, the current practice is that on a system supporting
+  dnl There is no formal standard regarding lib, lib32, and lib64.
+  dnl On most glibc systems, the current practice is that on a system supporting
   dnl 32-bit and 64-bit instruction sets or ABIs, 64-bit libraries go under
-  dnl $prefix/lib64 and 32-bit libraries go under $prefix/lib. We determine
-  dnl the compiler's default mode by looking at the compiler's library search
-  dnl path. If at least one of its elements ends in /lib64 or points to a
-  dnl directory whose absolute pathname ends in /lib64, we assume a 64-bit ABI.
-  dnl Otherwise we use the default, namely "lib".
+  dnl $prefix/lib64 and 32-bit libraries go under $prefix/lib. However, on
+  dnl Arch Linux based distributions, it's the opposite: 32-bit libraries go
+  dnl under $prefix/lib32 and 64-bit libraries go under $prefix/lib.
+  dnl We determine the compiler's default mode by looking at the compiler's
+  dnl library search path. If at least one of its elements ends in /lib64 or
+  dnl points to a directory whose absolute pathname ends in /lib64, we use that
+  dnl for 64-bit ABIs. Similarly for 32-bit ABIs. Otherwise we use the default,
+  dnl namely "lib".
   dnl On Solaris systems, the current practice is that on a system supporting
   dnl 32-bit and 64-bit instruction sets or ABIs, 64-bit libraries go under
   dnl $prefix/lib/64 (which is a symlink to either $prefix/lib/sparcv9 or
   dnl $prefix/lib/amd64) and 32-bit libraries go under $prefix/lib.
   AC_REQUIRE([AC_CANONICAL_HOST])
-  acl_libdirstem=lib
-  acl_libdirstem2=
-  case "$host_os" in
-    solaris*)
-      dnl See Solaris 10 Software Developer Collection > Solaris 64-bit Developer's Guide > The Development Environment
-      dnl <http://docs.sun.com/app/docs/doc/816-5138/dev-env?l=en&a=view>.
-      dnl "Portable Makefiles should refer to any library directories using the 64 symbolic link."
-      dnl But we want to recognize the sparcv9 or amd64 subdirectory also if the
-      dnl symlink is missing, so we set acl_libdirstem2 too.
-      AC_CACHE_CHECK([for 64-bit host], [gl_cv_solaris_64bit],
-        [AC_EGREP_CPP([sixtyfour bits], [
-#ifdef _LP64
-sixtyfour bits
-#endif
-           ], [gl_cv_solaris_64bit=yes], [gl_cv_solaris_64bit=no])
-        ])
-      if test $gl_cv_solaris_64bit = yes; then
-        acl_libdirstem=lib/64
-        case "$host_cpu" in
-          sparc*)        acl_libdirstem2=lib/sparcv9 ;;
-          i*86 | x86_64) acl_libdirstem2=lib/amd64 ;;
-        esac
-      fi
-      ;;
-    *)
-      searchpath=`(LC_ALL=C $CC -print-search-dirs) 2>/dev/null | sed -n -e 's,^libraries: ,,p' | sed -e 's,^=,,'`
-      if test -n "$searchpath"; then
-        acl_save_IFS="${IFS=    }"; IFS=":"
-        for searchdir in $searchpath; do
-          if test -d "$searchdir"; then
-            case "$searchdir" in
-              */lib64/ | */lib64 ) acl_libdirstem=lib64 ;;
-              */../ | */.. )
-                # Better ignore directories of this form. They are misleading.
-                ;;
-              *) searchdir=`cd "$searchdir" && pwd`
-                 case "$searchdir" in
-                   */lib64 ) acl_libdirstem=lib64 ;;
-                 esac ;;
-            esac
-          fi
-        done
-        IFS="$acl_save_IFS"
-      fi
-      ;;
-  esac
-  test -n "$acl_libdirstem2" || acl_libdirstem2="$acl_libdirstem"
+  AC_REQUIRE([gl_HOST_CPU_C_ABI_32BIT])
+
+  AC_CACHE_CHECK([for ELF binary format], [gl_cv_elf],
+    [AC_EGREP_CPP([Extensible Linking Format],
+       [#if defined __ELF__ || (defined __linux__ && defined __EDG__)
+        Extensible Linking Format
+        #endif
+       ],
+       [gl_cv_elf=yes],
+       [gl_cv_elf=no])
+    ])
+  if test $gl_cv_elf = yes; then
+    # Extract the ELF class of a file (5th byte) in decimal.
+    # Cf. https://en.wikipedia.org/wiki/Executable_and_Linkable_Format#File_header
+    if od -A x < /dev/null >/dev/null 2>/dev/null; then
+      # Use POSIX od.
+      func_elfclass ()
+      {
+        od -A n -t d1 -j 4 -N 1
+      }
+    else
+      # Use BSD hexdump.
+      func_elfclass ()
+      {
+        dd bs=1 count=1 skip=4 2>/dev/null | hexdump -e '1/1 "%3d "'
+        echo
+      }
+    fi
+    # Use 'expr', not 'test', to compare the values of func_elfclass, because on
+    # Solaris 11 OpenIndiana and Solaris 11 OmniOS, the result is 001 or 002,
+    # not 1 or 2.
+changequote(,)dnl
+    case $HOST_CPU_C_ABI_32BIT in
+      yes)
+        # 32-bit ABI.
+        acl_is_expected_elfclass ()
+        {
+          expr "`func_elfclass | sed -e 's/[    ]//g'`" = 1 > /dev/null
+        }
+        ;;
+      no)
+        # 64-bit ABI.
+        acl_is_expected_elfclass ()
+        {
+          expr "`func_elfclass | sed -e 's/[    ]//g'`" = 2 > /dev/null
+        }
+        ;;
+      *)
+        # Unknown.
+        acl_is_expected_elfclass ()
+        {
+          :
+        }
+        ;;
+    esac
+changequote([,])dnl
+  else
+    acl_is_expected_elfclass ()
+    {
+      :
+    }
+  fi
+
+  dnl Allow the user to override the result by setting acl_cv_libdirstems.
+  AC_CACHE_CHECK([for the common suffixes of directories in the library search path],
+    [acl_cv_libdirstems],
+    [dnl Try 'lib' first, because that's the default for libdir in GNU, see
+     dnl <https://www.gnu.org/prep/standards/html_node/Directory-Variables.html>.
+     acl_libdirstem=lib
+     acl_libdirstem2=
+     acl_libdirstem3=
+     case "$host_os" in
+       solaris*)
+         dnl See Solaris 10 Software Developer Collection > Solaris 64-bit Developer's Guide > The Development Environment
+         dnl <https://docs.oracle.com/cd/E19253-01/816-5138/dev-env/index.html>.
+         dnl "Portable Makefiles should refer to any library directories using the 64 symbolic link."
+         dnl But we want to recognize the sparcv9 or amd64 subdirectory also if the
+         dnl symlink is missing, so we set acl_libdirstem2 too.
+         if test $HOST_CPU_C_ABI_32BIT = no; then
+           acl_libdirstem2=lib/64
+           case "$host_cpu" in
+             sparc*)        acl_libdirstem3=lib/sparcv9 ;;
+             i*86 | x86_64) acl_libdirstem3=lib/amd64 ;;
+           esac
+         fi
+         ;;
+       *)
+         dnl If $CC generates code for a 32-bit ABI, the libraries are
+         dnl surely under $prefix/lib or $prefix/lib32, not $prefix/lib64.
+         dnl Similarly, if $CC generates code for a 64-bit ABI, the libraries
+         dnl are surely under $prefix/lib or $prefix/lib64, not $prefix/lib32.
+         dnl Find the compiler's search path. However, non-system compilers
+         dnl sometimes have odd library search paths. But we can't simply invoke
+         dnl '/usr/bin/gcc -print-search-dirs' because that would not take into
+         dnl account the -m32/-m31 or -m64 options from the $CC or $CFLAGS.
+         searchpath=`(LC_ALL=C $CC $CPPFLAGS $CFLAGS -print-search-dirs) 2>/dev/null \
+                     | sed -n -e 's,^libraries: ,,p' | sed -e 's,^=,,'`
+         if test $HOST_CPU_C_ABI_32BIT != no; then
+           # 32-bit or unknown ABI.
+           if test -d /usr/lib32; then
+             acl_libdirstem2=lib32
+           fi
+         fi
+         if test $HOST_CPU_C_ABI_32BIT != yes; then
+           # 64-bit or unknown ABI.
+           if test -d /usr/lib64; then
+             acl_libdirstem3=lib64
+           fi
+         fi
+         if test -n "$searchpath"; then
+           acl_save_IFS="${IFS=         }"; IFS=":"
+           for searchdir in $searchpath; do
+             if test -d "$searchdir"; then
+               case "$searchdir" in
+                 */lib32/ | */lib32 ) acl_libdirstem2=lib32 ;;
+                 */lib64/ | */lib64 ) acl_libdirstem3=lib64 ;;
+                 */../ | */.. )
+                   # Better ignore directories of this form. They are misleading.
+                   ;;
+                 *) searchdir=`cd "$searchdir" && pwd`
+                    case "$searchdir" in
+                      */lib32 ) acl_libdirstem2=lib32 ;;
+                      */lib64 ) acl_libdirstem3=lib64 ;;
+                    esac ;;
+               esac
+             fi
+           done
+           IFS="$acl_save_IFS"
+           if test $HOST_CPU_C_ABI_32BIT = yes; then
+             # 32-bit ABI.
+             acl_libdirstem3=
+           fi
+           if test $HOST_CPU_C_ABI_32BIT = no; then
+             # 64-bit ABI.
+             acl_libdirstem2=
+           fi
+         fi
+         ;;
+     esac
+     test -n "$acl_libdirstem2" || acl_libdirstem2="$acl_libdirstem"
+     test -n "$acl_libdirstem3" || acl_libdirstem3="$acl_libdirstem"
+     acl_cv_libdirstems="$acl_libdirstem,$acl_libdirstem2,$acl_libdirstem3"
+    ])
+  dnl Decompose acl_cv_libdirstems into acl_libdirstem, acl_libdirstem2, and
+  dnl acl_libdirstem3.
+changequote(,)dnl
+  acl_libdirstem=`echo "$acl_cv_libdirstems" | sed -e 's/,.*//'`
+  acl_libdirstem2=`echo "$acl_cv_libdirstems" | sed -e 's/^[^,]*,//' -e 's/,.*//'`
+  acl_libdirstem3=`echo "$acl_cv_libdirstems" | sed -e 's/^[^,]*,[^,]*,//' -e 's/,.*//'`
+changequote([,])dnl
 ])
diff --git a/gl/m4/limits-h.m4 b/gl/m4/limits-h.m4
new file mode 100644
index 00000000..5088fa16
--- /dev/null
+++ b/gl/m4/limits-h.m4
@@ -0,0 +1,41 @@
+dnl Check whether limits.h has needed features.
+
+dnl Copyright 2016-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Paul Eggert.
+
+AC_DEFUN_ONCE([gl_LIMITS_H],
+[
+  gl_CHECK_NEXT_HEADERS([limits.h])
+
+  AC_CACHE_CHECK([whether limits.h has WORD_BIT, BOOL_WIDTH etc.],
+    [gl_cv_header_limits_width],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#ifndef __STDC_WANT_IEC_60559_BFP_EXT__
+             #define __STDC_WANT_IEC_60559_BFP_EXT__ 1
+            #endif
+            #include <limits.h>
+            long long llm = LLONG_MAX;
+            int wb = WORD_BIT;
+            int ullw = ULLONG_WIDTH;
+            int bw = BOOL_WIDTH;
+          ]])],
+       [gl_cv_header_limits_width=yes],
+       [gl_cv_header_limits_width=no])])
+  if test "$gl_cv_header_limits_width" = yes; then
+    GL_GENERATE_LIMITS_H=false
+  else
+    GL_GENERATE_LIMITS_H=true
+  fi
+])
+
+dnl Unconditionally enables the replacement of <limits.h>.
+AC_DEFUN([gl_REPLACE_LIMITS_H],
+[
+  AC_REQUIRE([gl_LIMITS_H])
+  GL_GENERATE_LIMITS_H=true
+])
diff --git a/gl/m4/localcharset.m4 b/gl/m4/localcharset.m4
index 2e93e581..15b6b2a5 100644
--- a/gl/m4/localcharset.m4
+++ b/gl/m4/localcharset.m4
@@ -1,5 +1,5 @@
-# localcharset.m4 serial 7
-dnl Copyright (C) 2002, 2004, 2006, 2009-2013 Free Software Foundation, Inc.
+# localcharset.m4 serial 8
+dnl Copyright (C) 2002, 2004, 2006, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -8,10 +8,4 @@ AC_DEFUN([gl_LOCALCHARSET],
 [
   dnl Prerequisites of lib/localcharset.c.
   AC_REQUIRE([AM_LANGINFO_CODESET])
-  AC_REQUIRE([gl_FCNTL_O_FLAGS])
-  AC_CHECK_DECLS_ONCE([getc_unlocked])
-
-  dnl Prerequisites of the lib/Makefile.am snippet.
-  AC_REQUIRE([AC_CANONICAL_HOST])
-  AC_REQUIRE([gl_GLIBC21])
 ])
diff --git a/gl/m4/locale-fr.m4 b/gl/m4/locale-fr.m4
index ef199e39..8c41fadf 100644
--- a/gl/m4/locale-fr.m4
+++ b/gl/m4/locale-fr.m4
@@ -1,5 +1,5 @@
-# locale-fr.m4 serial 17
-dnl Copyright (C) 2003, 2005-2013 Free Software Foundation, Inc.
+# locale-fr.m4 serial 20
+dnl Copyright (C) 2003, 2005-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -12,8 +12,7 @@ AC_DEFUN([gt_LOCALE_FR],
   AC_REQUIRE([AC_CANONICAL_HOST])
   AC_REQUIRE([AM_LANGINFO_CODESET])
   AC_CACHE_CHECK([for a traditional french locale], [gt_cv_locale_fr], [
-    AC_LANG_CONFTEST([AC_LANG_SOURCE([
-changequote(,)dnl
+    AC_LANG_CONFTEST([AC_LANG_SOURCE([[
 #include <locale.h>
 #include <time.h>
 #if HAVE_LANGINFO_CODESET
@@ -24,8 +23,14 @@ changequote(,)dnl
 struct tm t;
 char buf[16];
 int main () {
+  /* On BeOS and Haiku, locales are not implemented in libc.  Rather, libintl
+     imitates locale dependent behaviour by looking at the environment
+     variables, and all locales use the UTF-8 encoding.  */
+#if defined __BEOS__ || defined __HAIKU__
+  return 1;
+#else
   /* Check whether the given locale name is recognized by the system.  */
-#if (defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__
+# if defined _WIN32 && !defined __CYGWIN__
   /* On native Windows, setlocale(category, "") looks at the system settings,
      not at the environment variables.  Also, when an encoding suffix such
      as ".65001" or ".54936" is specified, it succeeds but sets the LC_CTYPE
@@ -33,9 +38,9 @@ int main () {
   if (setlocale (LC_ALL, getenv ("LC_ALL")) == NULL
       || strcmp (setlocale (LC_CTYPE, NULL), "C") == 0)
     return 1;
-#else
+# else
   if (setlocale (LC_ALL, "") == NULL) return 1;
-#endif
+# endif
   /* Check whether nl_langinfo(CODESET) is nonempty and not "ASCII" or "646".
      On Mac OS X 10.3.5 (Darwin 7.5) in the fr_FR locale, nl_langinfo(CODESET)
      is empty, and the behaviour of Tcl 8.4 in this locale is not useful.
@@ -44,35 +49,35 @@ int main () {
      some unit tests fail.
      On MirBSD 10, when an unsupported locale is specified, setlocale()
      succeeds but then nl_langinfo(CODESET) is "UTF-8".  */
-#if HAVE_LANGINFO_CODESET
+# if HAVE_LANGINFO_CODESET
   {
     const char *cs = nl_langinfo (CODESET);
     if (cs[0] == '\0' || strcmp (cs, "ASCII") == 0 || strcmp (cs, "646") == 0
         || strcmp (cs, "UTF-8") == 0)
       return 1;
   }
-#endif
-#ifdef __CYGWIN__
+# endif
+# ifdef __CYGWIN__
   /* On Cygwin, avoid locale names without encoding suffix, because the
      locale_charset() function relies on the encoding suffix.  Note that
      LC_ALL is set on the command line.  */
   if (strchr (getenv ("LC_ALL"), '.') == NULL) return 1;
-#endif
+# endif
   /* Check whether in the abbreviation of the second month, the second
      character (should be U+00E9: LATIN SMALL LETTER E WITH ACUTE) is only
      one byte long. This excludes the UTF-8 encoding.  */
   t.tm_year = 1975 - 1900; t.tm_mon = 2 - 1; t.tm_mday = 4;
   if (strftime (buf, sizeof (buf), "%b", &t) < 3 || buf[2] != 'v') return 1;
-#if !defined __BIONIC__ /* Bionic libc's 'struct lconv' is just a dummy.  */
+# if !defined __BIONIC__ /* Bionic libc's 'struct lconv' is just a dummy.  */
   /* Check whether the decimal separator is a comma.
      On NetBSD 3.0 in the fr_FR.ISO8859-1 locale, localeconv()->decimal_point
      are nl_langinfo(RADIXCHAR) are both ".".  */
   if (localeconv () ->decimal_point[0] != ',') return 1;
-#endif
+# endif
   return 0;
+#endif
 }
-changequote([,])dnl
-      ])])
+      ]])])
     if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
       case "$host_os" in
         # Handle native Windows specially, because there setlocale() interprets
@@ -136,8 +141,7 @@ AC_DEFUN([gt_LOCALE_FR_UTF8],
 [
   AC_REQUIRE([AM_LANGINFO_CODESET])
   AC_CACHE_CHECK([for a french Unicode locale], [gt_cv_locale_fr_utf8], [
-    AC_LANG_CONFTEST([AC_LANG_SOURCE([
-changequote(,)dnl
+    AC_LANG_CONFTEST([AC_LANG_SOURCE([[
 #include <locale.h>
 #include <time.h>
 #if HAVE_LANGINFO_CODESET
@@ -153,7 +157,7 @@ int main () {
      variables, and all locales use the UTF-8 encoding.  */
 #if !(defined __BEOS__ || defined __HAIKU__)
   /* Check whether the given locale name is recognized by the system.  */
-# if (defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__
+# if defined _WIN32 && !defined __CYGWIN__
   /* On native Windows, setlocale(category, "") looks at the system settings,
      not at the environment variables.  Also, when an encoding suffix such
      as ".65001" or ".54936" is specified, it succeeds but sets the LC_CTYPE
@@ -199,8 +203,7 @@ int main () {
 #endif
   return 0;
 }
-changequote([,])dnl
-      ])])
+      ]])])
     if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
       case "$host_os" in
         # Handle native Windows specially, because there setlocale() interprets
diff --git a/gl/m4/locale-ja.m4 b/gl/m4/locale-ja.m4
index 132a3e77..25901730 100644
--- a/gl/m4/locale-ja.m4
+++ b/gl/m4/locale-ja.m4
@@ -1,5 +1,5 @@
-# locale-ja.m4 serial 12
-dnl Copyright (C) 2003, 2005-2013 Free Software Foundation, Inc.
+# locale-ja.m4 serial 15
+dnl Copyright (C) 2003, 2005-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -12,8 +12,7 @@ AC_DEFUN([gt_LOCALE_JA],
   AC_REQUIRE([AC_CANONICAL_HOST])
   AC_REQUIRE([AM_LANGINFO_CODESET])
   AC_CACHE_CHECK([for a traditional japanese locale], [gt_cv_locale_ja], [
-    AC_LANG_CONFTEST([AC_LANG_SOURCE([
-changequote(,)dnl
+    AC_LANG_CONFTEST([AC_LANG_SOURCE([[
 #include <locale.h>
 #include <time.h>
 #if HAVE_LANGINFO_CODESET
@@ -25,9 +24,14 @@ struct tm t;
 char buf[16];
 int main ()
 {
-  const char *p;
+  /* On BeOS and Haiku, locales are not implemented in libc.  Rather, libintl
+     imitates locale dependent behaviour by looking at the environment
+     variables, and all locales use the UTF-8 encoding.  */
+#if defined __BEOS__ || defined __HAIKU__
+  return 1;
+#else
   /* Check whether the given locale name is recognized by the system.  */
-#if (defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__
+# if defined _WIN32 && !defined __CYGWIN__
   /* On native Windows, setlocale(category, "") looks at the system settings,
      not at the environment variables.  Also, when an encoding suffix such
      as ".65001" or ".54936" is specified, it succeeds but sets the LC_CTYPE
@@ -35,9 +39,9 @@ int main ()
   if (setlocale (LC_ALL, getenv ("LC_ALL")) == NULL
       || strcmp (setlocale (LC_CTYPE, NULL), "C") == 0)
     return 1;
-#else
+# else
   if (setlocale (LC_ALL, "") == NULL) return 1;
-#endif
+# endif
   /* Check whether nl_langinfo(CODESET) is nonempty and not "ASCII" or "646".
      On Mac OS X 10.3.5 (Darwin 7.5) in the fr_FR locale, nl_langinfo(CODESET)
      is empty, and the behaviour of Tcl 8.4 in this locale is not useful.
@@ -46,35 +50,38 @@ int main ()
      some unit tests fail.
      On MirBSD 10, when an unsupported locale is specified, setlocale()
      succeeds but then nl_langinfo(CODESET) is "UTF-8".  */
-#if HAVE_LANGINFO_CODESET
+# if HAVE_LANGINFO_CODESET
   {
     const char *cs = nl_langinfo (CODESET);
     if (cs[0] == '\0' || strcmp (cs, "ASCII") == 0 || strcmp (cs, "646") == 0
         || strcmp (cs, "UTF-8") == 0)
       return 1;
   }
-#endif
-#ifdef __CYGWIN__
+# endif
+# ifdef __CYGWIN__
   /* On Cygwin, avoid locale names without encoding suffix, because the
      locale_charset() function relies on the encoding suffix.  Note that
      LC_ALL is set on the command line.  */
   if (strchr (getenv ("LC_ALL"), '.') == NULL) return 1;
-#endif
+# endif
   /* Check whether MB_CUR_MAX is > 1.  This excludes the dysfunctional locales
      on Cygwin 1.5.x.  */
   if (MB_CUR_MAX == 1)
     return 1;
   /* Check whether in a month name, no byte in the range 0x80..0x9F occurs.
      This excludes the UTF-8 encoding (except on MirBSD).  */
-  t.tm_year = 1975 - 1900; t.tm_mon = 2 - 1; t.tm_mday = 4;
-  if (strftime (buf, sizeof (buf), "%B", &t) < 2) return 1;
-  for (p = buf; *p != '\0'; p++)
-    if ((unsigned char) *p >= 0x80 && (unsigned char) *p < 0xa0)
-      return 1;
+  {
+    const char *p;
+    t.tm_year = 1975 - 1900; t.tm_mon = 2 - 1; t.tm_mday = 4;
+    if (strftime (buf, sizeof (buf), "%B", &t) < 2) return 1;
+    for (p = buf; *p != '\0'; p++)
+      if ((unsigned char) *p >= 0x80 && (unsigned char) *p < 0xa0)
+        return 1;
+  }
   return 0;
+#endif
 }
-changequote([,])dnl
-      ])])
+      ]])])
     if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
       case "$host_os" in
         # Handle native Windows specially, because there setlocale() interprets
diff --git a/gl/m4/locale-zh.m4 b/gl/m4/locale-zh.m4
index 4eed73f4..b9f9eef7 100644
--- a/gl/m4/locale-zh.m4
+++ b/gl/m4/locale-zh.m4
@@ -1,5 +1,5 @@
-# locale-zh.m4 serial 12
-dnl Copyright (C) 2003, 2005-2013 Free Software Foundation, Inc.
+# locale-zh.m4 serial 15
+dnl Copyright (C) 2003, 2005-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -12,8 +12,7 @@ AC_DEFUN([gt_LOCALE_ZH_CN],
   AC_REQUIRE([AC_CANONICAL_HOST])
   AC_REQUIRE([AM_LANGINFO_CODESET])
   AC_CACHE_CHECK([for a transitional chinese locale], [gt_cv_locale_zh_CN], [
-    AC_LANG_CONFTEST([AC_LANG_SOURCE([
-changequote(,)dnl
+    AC_LANG_CONFTEST([AC_LANG_SOURCE([[
 #include <locale.h>
 #include <stdlib.h>
 #include <time.h>
@@ -26,9 +25,14 @@ struct tm t;
 char buf[16];
 int main ()
 {
-  const char *p;
+  /* On BeOS and Haiku, locales are not implemented in libc.  Rather, libintl
+     imitates locale dependent behaviour by looking at the environment
+     variables, and all locales use the UTF-8 encoding.  */
+#if defined __BEOS__ || defined __HAIKU__
+  return 1;
+#else
   /* Check whether the given locale name is recognized by the system.  */
-#if (defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__
+# if defined _WIN32 && !defined __CYGWIN__
   /* On native Windows, setlocale(category, "") looks at the system settings,
      not at the environment variables.  Also, when an encoding suffix such
      as ".65001" or ".54936" is specified, it succeeds but sets the LC_CTYPE
@@ -36,9 +40,9 @@ int main ()
   if (setlocale (LC_ALL, getenv ("LC_ALL")) == NULL
       || strcmp (setlocale (LC_CTYPE, NULL), "C") == 0)
     return 1;
-#else
+# else
   if (setlocale (LC_ALL, "") == NULL) return 1;
-#endif
+# endif
   /* Check whether nl_langinfo(CODESET) is nonempty and not "ASCII" or "646".
      On Mac OS X 10.3.5 (Darwin 7.5) in the fr_FR locale, nl_langinfo(CODESET)
      is empty, and the behaviour of Tcl 8.4 in this locale is not useful.
@@ -47,35 +51,38 @@ int main ()
      some unit tests fail.
      On MirBSD 10, when an unsupported locale is specified, setlocale()
      succeeds but then nl_langinfo(CODESET) is "UTF-8".  */
-#if HAVE_LANGINFO_CODESET
+# if HAVE_LANGINFO_CODESET
   {
     const char *cs = nl_langinfo (CODESET);
     if (cs[0] == '\0' || strcmp (cs, "ASCII") == 0 || strcmp (cs, "646") == 0
         || strcmp (cs, "UTF-8") == 0)
       return 1;
   }
-#endif
-#ifdef __CYGWIN__
+# endif
+# ifdef __CYGWIN__
   /* On Cygwin, avoid locale names without encoding suffix, because the
      locale_charset() function relies on the encoding suffix.  Note that
      LC_ALL is set on the command line.  */
   if (strchr (getenv ("LC_ALL"), '.') == NULL) return 1;
-#endif
+# endif
   /* Check whether in a month name, no byte in the range 0x80..0x9F occurs.
      This excludes the UTF-8 encoding (except on MirBSD).  */
-  t.tm_year = 1975 - 1900; t.tm_mon = 2 - 1; t.tm_mday = 4;
-  if (strftime (buf, sizeof (buf), "%B", &t) < 2) return 1;
-  for (p = buf; *p != '\0'; p++)
-    if ((unsigned char) *p >= 0x80 && (unsigned char) *p < 0xa0)
-      return 1;
+  {
+    const char *p;
+    t.tm_year = 1975 - 1900; t.tm_mon = 2 - 1; t.tm_mday = 4;
+    if (strftime (buf, sizeof (buf), "%B", &t) < 2) return 1;
+    for (p = buf; *p != '\0'; p++)
+      if ((unsigned char) *p >= 0x80 && (unsigned char) *p < 0xa0)
+        return 1;
+  }
   /* Check whether a typical GB18030 multibyte sequence is recognized as a
      single wide character.  This excludes the GB2312 and GBK encodings.  */
   if (mblen ("\203\062\332\066", 5) != 4)
     return 1;
   return 0;
+#endif
 }
-changequote([,])dnl
-      ])])
+      ]])])
     if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
       case "$host_os" in
         # Handle native Windows specially, because there setlocale() interprets
diff --git a/gl/m4/locale_h.m4 b/gl/m4/locale_h.m4
index 8bd12e80..a33a0a46 100644
--- a/gl/m4/locale_h.m4
+++ b/gl/m4/locale_h.m4
@@ -1,13 +1,13 @@
-# locale_h.m4 serial 19
-dnl Copyright (C) 2007, 2009-2013 Free Software Foundation, Inc.
+# locale_h.m4 serial 28
+dnl Copyright (C) 2007, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-AC_DEFUN([gl_LOCALE_H],
+AC_DEFUN_ONCE([gl_LOCALE_H],
 [
-  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
-  dnl once only, before all statements that occur in other macros.
+  dnl Ensure to expand the default settings once only, before all statements
+  dnl that occur in other macros.
   AC_REQUIRE([gl_LOCALE_H_DEFAULTS])
 
   dnl Persuade glibc <locale.h> to define locale_t and the int_p_*, int_n_*
@@ -17,7 +17,9 @@ AC_DEFUN([gl_LOCALE_H],
   dnl If <stddef.h> is replaced, then <locale.h> must also be replaced.
   AC_REQUIRE([gl_STDDEF_H])
 
-  dnl Solaris 11 2011-11 defines the int_p_*, int_n_* members of 'struct lconv'
+  AC_REQUIRE([gl_LOCALE_T])
+
+  dnl Solaris 11.0 defines the int_p_*, int_n_* members of 'struct lconv'
   dnl only if _LCONV_C99 is defined.
   AC_REQUIRE([AC_CANONICAL_HOST])
   case "$host_os" in
@@ -37,34 +39,6 @@ AC_DEFUN([gl_LOCALE_H],
        [gl_cv_header_locale_h_posix2001=yes],
        [gl_cv_header_locale_h_posix2001=no])])
 
-  dnl Check for <xlocale.h>.
-  AC_CHECK_HEADERS_ONCE([xlocale.h])
-  if test $ac_cv_header_xlocale_h = yes; then
-    HAVE_XLOCALE_H=1
-    dnl Check whether use of locale_t requires inclusion of <xlocale.h>,
-    dnl e.g. on Mac OS X 10.5. If <locale.h> does not define locale_t by
-    dnl itself, we assume that <xlocale.h> will do so.
-    AC_CACHE_CHECK([whether locale.h defines locale_t],
-      [gl_cv_header_locale_has_locale_t],
-      [AC_COMPILE_IFELSE(
-         [AC_LANG_PROGRAM(
-            [[#include <locale.h>
-              locale_t x;]],
-            [[]])],
-         [gl_cv_header_locale_has_locale_t=yes],
-         [gl_cv_header_locale_has_locale_t=no])
-      ])
-    if test $gl_cv_header_locale_has_locale_t = yes; then
-      gl_cv_header_locale_h_needs_xlocale_h=no
-    else
-      gl_cv_header_locale_h_needs_xlocale_h=yes
-    fi
-  else
-    HAVE_XLOCALE_H=0
-    gl_cv_header_locale_h_needs_xlocale_h=no
-  fi
-  AC_SUBST([HAVE_XLOCALE_H])
-
   dnl Check whether 'struct lconv' is complete.
   dnl Bionic libc's 'struct lconv' is just a dummy.
   dnl On OpenBSD 4.9, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 9, Cygwin 1.5.x,
@@ -82,7 +56,20 @@ AC_DEFUN([gl_LOCALE_H],
        [gl_cv_sys_struct_lconv_ok=no])
     ])
   if test $gl_cv_sys_struct_lconv_ok = no; then
-    REPLACE_STRUCT_LCONV=1
+    dnl On native Windows with MSVC, merely define these member names as macros.
+    dnl This avoids trouble in C++ mode.
+    case "$host_os" in
+      mingw*)
+        AC_EGREP_CPP([Special], [
+#ifdef _MSC_VER
+ Special
+#endif
+          ],
+          [],
+          [REPLACE_STRUCT_LCONV=1])
+        ;;
+      *) REPLACE_STRUCT_LCONV=1 ;;
+    esac
   fi
 
   dnl <locale.h> is always overridden, because of GNULIB_POSIXCHECK.
@@ -96,27 +83,92 @@ AC_DEFUN([gl_LOCALE_H],
 # include <xlocale.h>
 #endif
     ]],
-    [setlocale duplocale])
+    [setlocale newlocale duplocale freelocale])
+])
+
+dnl Checks to determine whether the system has the locale_t type,
+dnl and how to obtain it.
+AC_DEFUN([gl_LOCALE_T],
+[
+  dnl Persuade glibc and Solaris <locale.h> to define locale_t.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  dnl Check whether use of locale_t requires inclusion of <xlocale.h>,
+  dnl e.g. on Mac OS X 10.5. If <locale.h> does not define locale_t by
+  dnl itself, we assume that <xlocale.h> will do so.
+  AC_CACHE_CHECK([whether locale.h defines locale_t],
+    [gl_cv_header_locale_has_locale_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <locale.h>
+            locale_t x;]],
+          [[]])],
+       [gl_cv_header_locale_has_locale_t=yes],
+       [gl_cv_header_locale_has_locale_t=no])
+    ])
+
+  dnl Check for <xlocale.h>.
+  AC_CHECK_HEADERS_ONCE([xlocale.h])
+  if test $ac_cv_header_xlocale_h = yes; then
+    HAVE_XLOCALE_H=1
+    if test $gl_cv_header_locale_has_locale_t = yes; then
+      gl_cv_header_locale_h_needs_xlocale_h=no
+    else
+      gl_cv_header_locale_h_needs_xlocale_h=yes
+    fi
+    HAVE_LOCALE_T=1
+  else
+    HAVE_XLOCALE_H=0
+    gl_cv_header_locale_h_needs_xlocale_h=no
+    if test $gl_cv_header_locale_has_locale_t = yes; then
+      HAVE_LOCALE_T=1
+    else
+      HAVE_LOCALE_T=0
+    fi
+  fi
+  AC_SUBST([HAVE_XLOCALE_H])
 ])
 
+# gl_LOCALE_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_LOCALE_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_LOCALE_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_LOCALE_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_LOCALE_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_LOCALE_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOCALECONV])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SETLOCALE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SETLOCALE_NULL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_DUPLOCALE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOCALENAME])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_LOCALE_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_LOCALE_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_LOCALE_H_DEFAULTS],
 [
-  GNULIB_LOCALECONV=0; AC_SUBST([GNULIB_LOCALECONV])
-  GNULIB_SETLOCALE=0;  AC_SUBST([GNULIB_SETLOCALE])
-  GNULIB_DUPLOCALE=0;  AC_SUBST([GNULIB_DUPLOCALE])
   dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_NEWLOCALE=1;       AC_SUBST([HAVE_NEWLOCALE])
   HAVE_DUPLOCALE=1;       AC_SUBST([HAVE_DUPLOCALE])
+  HAVE_FREELOCALE=1;      AC_SUBST([HAVE_FREELOCALE])
   REPLACE_LOCALECONV=0;   AC_SUBST([REPLACE_LOCALECONV])
   REPLACE_SETLOCALE=0;    AC_SUBST([REPLACE_SETLOCALE])
+  REPLACE_NEWLOCALE=0;    AC_SUBST([REPLACE_NEWLOCALE])
   REPLACE_DUPLOCALE=0;    AC_SUBST([REPLACE_DUPLOCALE])
+  REPLACE_FREELOCALE=0;   AC_SUBST([REPLACE_FREELOCALE])
   REPLACE_STRUCT_LCONV=0; AC_SUBST([REPLACE_STRUCT_LCONV])
+  LOCALENAME_ENHANCE_LOCALE_FUNCS=0; AC_SUBST([LOCALENAME_ENHANCE_LOCALE_FUNCS])
 ])
diff --git a/gl/m4/localeconv.m4 b/gl/m4/localeconv.m4
index b8bb5964..ae225fed 100644
--- a/gl/m4/localeconv.m4
+++ b/gl/m4/localeconv.m4
@@ -1,5 +1,5 @@
 # localeconv.m4 serial 1
-dnl Copyright (C) 2012-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2012-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/lock.m4 b/gl/m4/lock.m4
index aae1701a..88cf5575 100644
--- a/gl/m4/lock.m4
+++ b/gl/m4/lock.m4
@@ -1,5 +1,5 @@
-# lock.m4 serial 13 (gettext-0.18.2)
-dnl Copyright (C) 2005-2013 Free Software Foundation, Inc.
+# lock.m4 serial 14
+dnl Copyright (C) 2005-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -12,11 +12,16 @@ AC_DEFUN([gl_LOCK],
   if test "$gl_threads_api" = posix; then
     # OSF/1 4.0 and Mac OS X 10.1 lack the pthread_rwlock_t type and the
     # pthread_rwlock_* functions.
+    has_rwlock=false
     AC_CHECK_TYPE([pthread_rwlock_t],
-      [AC_DEFINE([HAVE_PTHREAD_RWLOCK], [1],
+      [has_rwlock=true
+       AC_DEFINE([HAVE_PTHREAD_RWLOCK], [1],
          [Define if the POSIX multithreading library has read/write locks.])],
       [],
       [#include <pthread.h>])
+    if $has_rwlock; then
+      gl_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER
+    fi
     # glibc defines PTHREAD_MUTEX_RECURSIVE as enum, not as a macro.
     AC_COMPILE_IFELSE([
       AC_LANG_PROGRAM(
diff --git a/gl/m4/longlong.m4 b/gl/m4/longlong.m4
deleted file mode 100644
index 3af6ab5a..00000000
--- a/gl/m4/longlong.m4
+++ /dev/null
@@ -1,113 +0,0 @@
-# longlong.m4 serial 17
-dnl Copyright (C) 1999-2007, 2009-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-dnl From Paul Eggert.
-
-# Define HAVE_LONG_LONG_INT if 'long long int' works.
-# This fixes a bug in Autoconf 2.61, and can be faster
-# than what's in Autoconf 2.62 through 2.68.
-
-# Note: If the type 'long long int' exists but is only 32 bits large
-# (as on some very old compilers), HAVE_LONG_LONG_INT will not be
-# defined. In this case you can treat 'long long int' like 'long int'.
-
-AC_DEFUN([AC_TYPE_LONG_LONG_INT],
-[
-  AC_REQUIRE([AC_TYPE_UNSIGNED_LONG_LONG_INT])
-  AC_CACHE_CHECK([for long long int], [ac_cv_type_long_long_int],
-     [ac_cv_type_long_long_int=yes
-      if test "x${ac_cv_prog_cc_c99-no}" = xno; then
-        ac_cv_type_long_long_int=$ac_cv_type_unsigned_long_long_int
-        if test $ac_cv_type_long_long_int = yes; then
-          dnl Catch a bug in Tandem NonStop Kernel (OSS) cc -O circa 2004.
-          dnl If cross compiling, assume the bug is not important, since
-          dnl nobody cross compiles for this platform as far as we know.
-          AC_RUN_IFELSE(
-            [AC_LANG_PROGRAM(
-               [[@%:@include <limits.h>
-                 @%:@ifndef LLONG_MAX
-                 @%:@ define HALF \
-                          (1LL << (sizeof (long long int) * CHAR_BIT - 2))
-                 @%:@ define LLONG_MAX (HALF - 1 + HALF)
-                 @%:@endif]],
-               [[long long int n = 1;
-                 int i;
-                 for (i = 0; ; i++)
-                   {
-                     long long int m = n << i;
-                     if (m >> i != n)
-                       return 1;
-                     if (LLONG_MAX / 2 < m)
-                       break;
-                   }
-                 return 0;]])],
-            [],
-            [ac_cv_type_long_long_int=no],
-            [:])
-        fi
-      fi])
-  if test $ac_cv_type_long_long_int = yes; then
-    AC_DEFINE([HAVE_LONG_LONG_INT], [1],
-      [Define to 1 if the system has the type 'long long int'.])
-  fi
-])
-
-# Define HAVE_UNSIGNED_LONG_LONG_INT if 'unsigned long long int' works.
-# This fixes a bug in Autoconf 2.61, and can be faster
-# than what's in Autoconf 2.62 through 2.68.
-
-# Note: If the type 'unsigned long long int' exists but is only 32 bits
-# large (as on some very old compilers), AC_TYPE_UNSIGNED_LONG_LONG_INT
-# will not be defined. In this case you can treat 'unsigned long long int'
-# like 'unsigned long int'.
-
-AC_DEFUN([AC_TYPE_UNSIGNED_LONG_LONG_INT],
-[
-  AC_CACHE_CHECK([for unsigned long long int],
-    [ac_cv_type_unsigned_long_long_int],
-    [ac_cv_type_unsigned_long_long_int=yes
-     if test "x${ac_cv_prog_cc_c99-no}" = xno; then
-       AC_LINK_IFELSE(
-         [_AC_TYPE_LONG_LONG_SNIPPET],
-         [],
-         [ac_cv_type_unsigned_long_long_int=no])
-     fi])
-  if test $ac_cv_type_unsigned_long_long_int = yes; then
-    AC_DEFINE([HAVE_UNSIGNED_LONG_LONG_INT], [1],
-      [Define to 1 if the system has the type 'unsigned long long int'.])
-  fi
-])
-
-# Expands to a C program that can be used to test for simultaneous support
-# of 'long long' and 'unsigned long long'. We don't want to say that
-# 'long long' is available if 'unsigned long long' is not, or vice versa,
-# because too many programs rely on the symmetry between signed and unsigned
-# integer types (excluding 'bool').
-AC_DEFUN([_AC_TYPE_LONG_LONG_SNIPPET],
-[
-  AC_LANG_PROGRAM(
-    [[/* For now, do not test the preprocessor; as of 2007 there are too many
-         implementations with broken preprocessors.  Perhaps this can
-         be revisited in 2012.  In the meantime, code should not expect
-         #if to work with literals wider than 32 bits.  */
-      /* Test literals.  */
-      long long int ll = 9223372036854775807ll;
-      long long int nll = -9223372036854775807LL;
-      unsigned long long int ull = 18446744073709551615ULL;
-      /* Test constant expressions.   */
-      typedef int a[((-9223372036854775807LL < 0 && 0 < 9223372036854775807ll)
-                     ? 1 : -1)];
-      typedef int b[(18446744073709551615ULL <= (unsigned long long int) -1
-                     ? 1 : -1)];
-      int i = 63;]],
-    [[/* Test availability of runtime routines for shift and division.  */
-      long long int llmax = 9223372036854775807ll;
-      unsigned long long int ullmax = 18446744073709551615ull;
-      return ((ll << 63) | (ll >> 63) | (ll < i) | (ll > i)
-              | (llmax / ll) | (llmax % ll)
-              | (ull << 63) | (ull >> 63) | (ull << i) | (ull >> i)
-              | (ullmax / ull) | (ullmax % ull));]])
-])
diff --git a/gl/m4/ls-mntd-fs.m4 b/gl/m4/ls-mntd-fs.m4
deleted file mode 100644
index fb116c8b..00000000
--- a/gl/m4/ls-mntd-fs.m4
+++ /dev/null
@@ -1,357 +0,0 @@
-# serial 30
-# How to list mounted file systems.
-
-# Copyright (C) 1998-2004, 2006, 2009-2013 Free Software Foundation, Inc.
-#
-# This file is free software; the Free Software Foundation
-# gives unlimited permission to copy and/or distribute it,
-# with or without modifications, as long as this notice is preserved.
-
-dnl From Jim Meyering.
-dnl
-dnl This is not pretty.  I've just taken the autoconf code and wrapped
-dnl it in an AC_DEFUN and made some other fixes.
-dnl
-
-# Replace Autoconf's AC_FUNC_GETMNTENT to work around a bug in Autoconf
-# through Autoconf 2.59.  We can remove this once we assume Autoconf 2.60
-# or later.
-AC_DEFUN([AC_FUNC_GETMNTENT],
-[# getmntent is in the standard C library on UNICOS, in -lsun on Irix 4,
-# -lseq on Dynix/PTX, -lgen on Unixware.
-AC_SEARCH_LIBS([getmntent], [sun seq gen])
-AC_CHECK_FUNCS([getmntent])
-])
-
-# gl_LIST_MOUNTED_FILE_SYSTEMS([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
-AC_DEFUN([gl_LIST_MOUNTED_FILE_SYSTEMS],
-  [
-AC_CHECK_FUNCS([listmntent getmntinfo])
-AC_CHECK_HEADERS_ONCE([sys/param.h sys/statvfs.h])
-
-# We must include grp.h before ucred.h on OSF V4.0, since ucred.h uses
-# NGROUPS (as the array dimension for a struct member) without a definition.
-AC_CHECK_HEADERS([sys/ucred.h], [], [], [#include <grp.h>])
-
-AC_CHECK_HEADERS([sys/mount.h], [], [],
-  [AC_INCLUDES_DEFAULT
-   [#if HAVE_SYS_PARAM_H
-     #include <sys/param.h>
-    #endif]])
-
-AC_CHECK_HEADERS([mntent.h sys/fs_types.h])
-    getfsstat_includes="\
-$ac_includes_default
-#if HAVE_SYS_PARAM_H
-# include <sys/param.h> /* needed by powerpc-apple-darwin1.3.7 */
-#endif
-#if HAVE_SYS_UCRED_H
-# include <grp.h> /* needed for definition of NGROUPS */
-# include <sys/ucred.h> /* needed by powerpc-apple-darwin1.3.7 */
-#endif
-#if HAVE_SYS_MOUNT_H
-# include <sys/mount.h>
-#endif
-#if HAVE_SYS_FS_TYPES_H
-# include <sys/fs_types.h> /* needed by powerpc-apple-darwin1.3.7 */
-#endif
-"
-AC_CHECK_MEMBERS([struct fsstat.f_fstypename],,,[$getfsstat_includes])
-
-# Determine how to get the list of mounted file systems.
-ac_list_mounted_fs=
-
-# If the getmntent function is available but not in the standard library,
-# make sure LIBS contains the appropriate -l option.
-AC_FUNC_GETMNTENT
-
-# This test must precede the ones for getmntent because Unicos-9 is
-# reported to have the getmntent function, but its support is incompatible
-# with other getmntent implementations.
-
-# NOTE: Normally, I wouldn't use a check for system type as I've done for
-# 'CRAY' below since that goes against the whole autoconf philosophy.  But
-# I think there is too great a chance that some non-Cray system has a
-# function named listmntent to risk the false positive.
-
-if test -z "$ac_list_mounted_fs"; then
-  # Cray UNICOS 9
-  AC_MSG_CHECKING([for listmntent of Cray/Unicos-9])
-  AC_CACHE_VAL([fu_cv_sys_mounted_cray_listmntent],
-    [fu_cv_sys_mounted_cray_listmntent=no
-      AC_EGREP_CPP([yes],
-        [#ifdef _CRAY
-yes
-#endif
-        ], [test $ac_cv_func_listmntent = yes \
-            && fu_cv_sys_mounted_cray_listmntent=yes]
-      )
-    ]
-  )
-  AC_MSG_RESULT([$fu_cv_sys_mounted_cray_listmntent])
-  if test $fu_cv_sys_mounted_cray_listmntent = yes; then
-    ac_list_mounted_fs=found
-    AC_DEFINE([MOUNTED_LISTMNTENT], [1],
-      [Define if there is a function named listmntent that can be used to
-       list all mounted file systems.  (UNICOS)])
-  fi
-fi
-
-if test -z "$ac_list_mounted_fs"; then
-  # AIX.
-  AC_MSG_CHECKING([for mntctl function and struct vmount])
-  AC_CACHE_VAL([fu_cv_sys_mounted_vmount],
-  [AC_PREPROC_IFELSE([AC_LANG_SOURCE([[#include <fshelp.h>]])],
-    [fu_cv_sys_mounted_vmount=yes],
-    [fu_cv_sys_mounted_vmount=no])])
-  AC_MSG_RESULT([$fu_cv_sys_mounted_vmount])
-  if test $fu_cv_sys_mounted_vmount = yes; then
-    ac_list_mounted_fs=found
-    AC_DEFINE([MOUNTED_VMOUNT], [1],
-        [Define if there is a function named mntctl that can be used to read
-         the list of mounted file systems, and there is a system header file
-         that declares 'struct vmount'.  (AIX)])
-  fi
-fi
-
-if test $ac_cv_func_getmntent = yes; then
-
-  # This system has the getmntent function.
-  # Determine whether it's the one-argument variant or the two-argument one.
-
-  if test -z "$ac_list_mounted_fs"; then
-    # 4.3BSD, SunOS, HP-UX, Dynix, Irix
-    AC_MSG_CHECKING([for one-argument getmntent function])
-    AC_CACHE_VAL([fu_cv_sys_mounted_getmntent1],
-                 [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-/* SunOS 4.1.x /usr/include/mntent.h needs this for FILE */
-#include <stdio.h>
-
-#include <mntent.h>
-#if !defined MOUNTED
-# if defined _PATH_MOUNTED      /* GNU libc  */
-#  define MOUNTED _PATH_MOUNTED
-# endif
-# if defined MNT_MNTTAB /* HP-UX.  */
-#  define MOUNTED MNT_MNTTAB
-# endif
-# if defined MNTTABNAME /* Dynix.  */
-#  define MOUNTED MNTTABNAME
-# endif
-#endif
-]],
-                      [[ struct mntent *mnt = 0; char *table = MOUNTED;
-                         if (sizeof mnt && sizeof table) return 0;]])],
-                    [fu_cv_sys_mounted_getmntent1=yes],
-                    [fu_cv_sys_mounted_getmntent1=no])])
-    AC_MSG_RESULT([$fu_cv_sys_mounted_getmntent1])
-    if test $fu_cv_sys_mounted_getmntent1 = yes; then
-      ac_list_mounted_fs=found
-      AC_DEFINE([MOUNTED_GETMNTENT1], [1],
-        [Define if there is a function named getmntent for reading the list
-         of mounted file systems, and that function takes a single argument.
-         (4.3BSD, SunOS, HP-UX, Dynix, Irix)])
-    fi
-  fi
-
-  if test -z "$ac_list_mounted_fs"; then
-    # SVR4
-    AC_MSG_CHECKING([for two-argument getmntent function])
-    AC_CACHE_VAL([fu_cv_sys_mounted_getmntent2],
-    [AC_EGREP_HEADER([getmntent], [sys/mnttab.h],
-      fu_cv_sys_mounted_getmntent2=yes,
-      fu_cv_sys_mounted_getmntent2=no)])
-    AC_MSG_RESULT([$fu_cv_sys_mounted_getmntent2])
-    if test $fu_cv_sys_mounted_getmntent2 = yes; then
-      ac_list_mounted_fs=found
-      AC_DEFINE([MOUNTED_GETMNTENT2], [1],
-        [Define if there is a function named getmntent for reading the list of
-         mounted file systems, and that function takes two arguments.  (SVR4)])
-      AC_CHECK_FUNCS([hasmntopt])
-    fi
-  fi
-
-fi
-
-if test -z "$ac_list_mounted_fs"; then
-  # DEC Alpha running OSF/1, and Apple Darwin 1.3.
-  # powerpc-apple-darwin1.3.7 needs sys/param.h sys/ucred.h sys/fs_types.h
-
-  AC_MSG_CHECKING([for getfsstat function])
-  AC_CACHE_VAL([fu_cv_sys_mounted_getfsstat],
-  [AC_LINK_IFELSE([AC_LANG_PROGRAM([[
-#include <sys/types.h>
-#if HAVE_STRUCT_FSSTAT_F_FSTYPENAME
-# define FS_TYPE(Ent) ((Ent).f_fstypename)
-#else
-# define FS_TYPE(Ent) mnt_names[(Ent).f_type]
-#endif
-$getfsstat_includes]]
-,
-      [[struct statfs *stats;
-        int numsys = getfsstat ((struct statfs *)0, 0L, MNT_WAIT);
-        char *t = FS_TYPE (*stats); ]])],
-    [fu_cv_sys_mounted_getfsstat=yes],
-    [fu_cv_sys_mounted_getfsstat=no])])
-  AC_MSG_RESULT([$fu_cv_sys_mounted_getfsstat])
-  if test $fu_cv_sys_mounted_getfsstat = yes; then
-    ac_list_mounted_fs=found
-    AC_DEFINE([MOUNTED_GETFSSTAT], [1],
-              [Define if there is a function named getfsstat for reading the
-               list of mounted file systems.  (DEC Alpha running OSF/1)])
-  fi
-fi
-
-if test -z "$ac_list_mounted_fs"; then
-  # SVR3
-  AC_MSG_CHECKING([for FIXME existence of three headers])
-  AC_CACHE_VAL([fu_cv_sys_mounted_fread_fstyp],
-    [AC_PREPROC_IFELSE([AC_LANG_SOURCE([[
-#include <sys/statfs.h>
-#include <sys/fstyp.h>
-#include <mnttab.h>]])],
-                       [fu_cv_sys_mounted_fread_fstyp=yes],
-                       [fu_cv_sys_mounted_fread_fstyp=no])])
-  AC_MSG_RESULT([$fu_cv_sys_mounted_fread_fstyp])
-  if test $fu_cv_sys_mounted_fread_fstyp = yes; then
-    ac_list_mounted_fs=found
-    AC_DEFINE([MOUNTED_FREAD_FSTYP], [1],
-      [Define if (like SVR2) there is no specific function for reading the
-       list of mounted file systems, and your system has these header files:
-       <sys/fstyp.h> and <sys/statfs.h>.  (SVR3)])
-  fi
-fi
-
-if test -z "$ac_list_mounted_fs"; then
-  # 4.4BSD and DEC OSF/1.
-  AC_MSG_CHECKING([for getmntinfo function])
-  AC_CACHE_VAL([fu_cv_sys_mounted_getmntinfo],
-    [
-      test "$ac_cv_func_getmntinfo" = yes \
-          && fu_cv_sys_mounted_getmntinfo=yes \
-          || fu_cv_sys_mounted_getmntinfo=no
-    ])
-  AC_MSG_RESULT([$fu_cv_sys_mounted_getmntinfo])
-  if test $fu_cv_sys_mounted_getmntinfo = yes; then
-    AC_MSG_CHECKING([whether getmntinfo returns statvfs structures])
-    AC_CACHE_VAL([fu_cv_sys_mounted_getmntinfo2],
-      [
-        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-#if HAVE_SYS_PARAM_H
-# include <sys/param.h>
-#endif
-#include <sys/types.h>
-#if HAVE_SYS_MOUNT_H
-# include <sys/mount.h>
-#endif
-#if HAVE_SYS_STATVFS_H
-# include <sys/statvfs.h>
-#endif
-extern
-#ifdef __cplusplus
-"C"
-#endif
-int getmntinfo (struct statfs **, int);
-            ]], [])],
-          [fu_cv_sys_mounted_getmntinfo2=no],
-          [fu_cv_sys_mounted_getmntinfo2=yes])
-      ])
-    AC_MSG_RESULT([$fu_cv_sys_mounted_getmntinfo2])
-    if test $fu_cv_sys_mounted_getmntinfo2 = no; then
-      ac_list_mounted_fs=found
-      AC_DEFINE([MOUNTED_GETMNTINFO], [1],
-                [Define if there is a function named getmntinfo for reading the
-                 list of mounted file systems and it returns an array of
-                 'struct statfs'.  (4.4BSD, Darwin)])
-    else
-      ac_list_mounted_fs=found
-      AC_DEFINE([MOUNTED_GETMNTINFO2], [1],
-                [Define if there is a function named getmntinfo for reading the
-                 list of mounted file systems and it returns an array of
-                 'struct statvfs'.  (NetBSD 3.0)])
-    fi
-  fi
-fi
-
-if test -z "$ac_list_mounted_fs"; then
-  # Ultrix
-  AC_MSG_CHECKING([for getmnt function])
-  AC_CACHE_VAL([fu_cv_sys_mounted_getmnt],
-    [AC_PREPROC_IFELSE([AC_LANG_SOURCE([[
-#include <sys/fs_types.h>
-#include <sys/mount.h>]])],
-                       [fu_cv_sys_mounted_getmnt=yes],
-                       [fu_cv_sys_mounted_getmnt=no])])
-  AC_MSG_RESULT([$fu_cv_sys_mounted_getmnt])
-  if test $fu_cv_sys_mounted_getmnt = yes; then
-    ac_list_mounted_fs=found
-    AC_DEFINE([MOUNTED_GETMNT], [1],
-      [Define if there is a function named getmnt for reading the list of
-       mounted file systems.  (Ultrix)])
-  fi
-fi
-
-if test -z "$ac_list_mounted_fs"; then
-  # BeOS
-  AC_CHECK_FUNCS([next_dev fs_stat_dev])
-  AC_CHECK_HEADERS([fs_info.h])
-  AC_MSG_CHECKING([for BEOS mounted file system support functions])
-  if test $ac_cv_header_fs_info_h = yes \
-      && test $ac_cv_func_next_dev = yes \
-        && test $ac_cv_func_fs_stat_dev = yes; then
-    fu_result=yes
-  else
-    fu_result=no
-  fi
-  AC_MSG_RESULT([$fu_result])
-  if test $fu_result = yes; then
-    ac_list_mounted_fs=found
-    AC_DEFINE([MOUNTED_FS_STAT_DEV], [1],
-      [Define if there are functions named next_dev and fs_stat_dev for
-       reading the list of mounted file systems.  (BeOS)])
-  fi
-fi
-
-if test -z "$ac_list_mounted_fs"; then
-  # SVR2
-  AC_MSG_CHECKING([whether it is possible to resort to fread on /etc/mnttab])
-  AC_CACHE_VAL([fu_cv_sys_mounted_fread],
-    [AC_PREPROC_IFELSE([AC_LANG_SOURCE([[#include <mnttab.h>]])],
-                       [fu_cv_sys_mounted_fread=yes],
-                       [fu_cv_sys_mounted_fread=no])])
-  AC_MSG_RESULT([$fu_cv_sys_mounted_fread])
-  if test $fu_cv_sys_mounted_fread = yes; then
-    ac_list_mounted_fs=found
-    AC_DEFINE([MOUNTED_FREAD], [1],
-              [Define if there is no specific function for reading the list of
-               mounted file systems.  fread will be used to read /etc/mnttab.
-               (SVR2) ])
-  fi
-fi
-
-if test -z "$ac_list_mounted_fs"; then
-  # Interix / BSD alike statvfs
-  # the code is really interix specific, so make sure, we're on it.
-  case "$host" in
-  *-interix*)
-    AC_CHECK_FUNCS([statvfs])
-    if test $ac_cv_func_statvfs = yes; then
-      ac_list_mounted_fs=found
-      AC_DEFINE([MOUNTED_INTERIX_STATVFS], [1],
-                [Define if we are on interix, and ought to use statvfs plus
-                 some special knowledge on where mounted file systems can be
-                 found. (Interix)])
-    fi
-    ;;
-  esac
-fi
-
-if test -z "$ac_list_mounted_fs"; then
-  AC_MSG_ERROR([could not determine how to read list of mounted file systems])
-  # FIXME -- no need to abort building the whole package
-  # Can't build mountlist.c or anything that needs its functions
-fi
-
-AS_IF([test $ac_list_mounted_fs = found], [$1], [$2])
-
-  ])
diff --git a/gl/m4/lseek.m4 b/gl/m4/lseek.m4
new file mode 100644
index 00000000..fd4f1f27
--- /dev/null
+++ b/gl/m4/lseek.m4
@@ -0,0 +1,78 @@
+# lseek.m4 serial 12
+dnl Copyright (C) 2007, 2009-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_LSEEK],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([AC_PROG_CC])
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+  AC_CACHE_CHECK([whether lseek detects pipes], [gl_cv_func_lseek_pipe],
+    [case "$host_os" in
+       mingw*)
+         dnl Native Windows.
+         dnl The result of lseek (fd, (off_t)0, SEEK_CUR) or
+         dnl SetFilePointer(handle, 0, NULL, FILE_CURRENT)
+         dnl for a pipe depends on the environment: In a Cygwin 1.5
+         dnl environment it succeeds (wrong); in a Cygwin 1.7 environment
+         dnl it fails with a wrong errno value.
+         gl_cv_func_lseek_pipe=no
+         ;;
+       *)
+         if test $cross_compiling = no; then
+           AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+#include <sys/types.h> /* for off_t */
+#include <stdio.h> /* for SEEK_CUR */
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#else /* on Windows with MSVC */
+# include <io.h>
+#endif
+]GL_MDA_DEFINES],
+[[
+  /* Exit with success only if stdin is seekable.  */
+  return lseek (0, (off_t)0, SEEK_CUR) < 0;
+]])],
+             [if test -s conftest$ac_exeext \
+                 && ./conftest$ac_exeext < conftest.$ac_ext \
+                 && test 1 = "`echo hi \
+                   | { ./conftest$ac_exeext; echo $?; cat >/dev/null; }`"; then
+                gl_cv_func_lseek_pipe=yes
+              else
+                gl_cv_func_lseek_pipe=no
+              fi
+             ],
+             [gl_cv_func_lseek_pipe=no])
+         else
+           AC_COMPILE_IFELSE(
+             [AC_LANG_SOURCE([[
+#if defined __BEOS__
+/* BeOS mistakenly return 0 when trying to seek on pipes.  */
+  Choke me.
+#endif]])],
+             [gl_cv_func_lseek_pipe=yes], [gl_cv_func_lseek_pipe=no])
+         fi
+         ;;
+     esac
+    ])
+  if test "$gl_cv_func_lseek_pipe" = no; then
+    REPLACE_LSEEK=1
+    AC_DEFINE([LSEEK_PIPE_BROKEN], [1],
+      [Define to 1 if lseek does not detect pipes.])
+  fi
+
+  AC_REQUIRE([gl_SYS_TYPES_H])
+  if test $WINDOWS_64_BIT_OFF_T = 1; then
+    REPLACE_LSEEK=1
+  fi
+
+  dnl macOS SEEK_DATA is incompatible with other platforms.
+  case $host_os in
+    darwin*)
+      REPLACE_LSEEK=1;;
+  esac
+])
diff --git a/gl/m4/malloc.m4 b/gl/m4/malloc.m4
index 4b24a0b1..55402924 100644
--- a/gl/m4/malloc.m4
+++ b/gl/m4/malloc.m4
@@ -1,98 +1,175 @@
-# malloc.m4 serial 14
-dnl Copyright (C) 2007, 2009-2013 Free Software Foundation, Inc.
+# malloc.m4 serial 28
+dnl Copyright (C) 2007, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-m4_version_prereq([2.70], [] ,[
-
-# This is taken from the following Autoconf patch:
-# http://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=commitdiff;h=7fbb553727ed7e0e689a17594b58559ecf3ea6e9
+# This is adapted with modifications from upstream Autoconf here:
+# https://git.savannah.gnu.org/cgit/autoconf.git/tree/lib/autoconf/functions.m4?id=v2.70#n949
 AC_DEFUN([_AC_FUNC_MALLOC_IF],
 [
-  AC_REQUIRE([AC_HEADER_STDC])dnl
   AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
-  AC_CHECK_HEADERS([stdlib.h])
-  AC_CACHE_CHECK([for GNU libc compatible malloc],
+  AC_CACHE_CHECK([whether malloc (0) returns nonnull],
     [ac_cv_func_malloc_0_nonnull],
     [AC_RUN_IFELSE(
        [AC_LANG_PROGRAM(
-          [[#if defined STDC_HEADERS || defined HAVE_STDLIB_H
-            # include <stdlib.h>
-            #else
-            char *malloc ();
-            #endif
+          [[#include <stdlib.h>
           ]],
-          [[return ! malloc (0);]])
+          [[void *p = malloc (0);
+            int result = !p;
+            free (p);
+            return result;]])
        ],
        [ac_cv_func_malloc_0_nonnull=yes],
        [ac_cv_func_malloc_0_nonnull=no],
        [case "$host_os" in
           # Guess yes on platforms where we know the result.
-          *-gnu* | freebsd* | netbsd* | openbsd* \
-          | hpux* | solaris* | cygwin* | mingw*)
-            ac_cv_func_malloc_0_nonnull=yes ;;
-          # If we don't know, assume the worst.
-          *) ac_cv_func_malloc_0_nonnull=no ;;
+          *-gnu* | freebsd* | netbsd* | openbsd* | bitrig* \
+          | gnu* | *-musl* | midnightbsd* \
+          | hpux* | solaris* | cygwin* | mingw* | msys* )
+            ac_cv_func_malloc_0_nonnull="guessing yes" ;;
+          # If we don't know, obey --enable-cross-guesses.
+          *) ac_cv_func_malloc_0_nonnull="$gl_cross_guess_normal" ;;
         esac
        ])
     ])
-  AS_IF([test $ac_cv_func_malloc_0_nonnull = yes], [$1], [$2])
+  AS_CASE([$ac_cv_func_malloc_0_nonnull], [*yes], [$1], [$2])
 ])# _AC_FUNC_MALLOC_IF
 
-])
-
 # gl_FUNC_MALLOC_GNU
 # ------------------
-# Test whether 'malloc (0)' is handled like in GNU libc, and replace malloc if
-# it is not.
+# Replace malloc if it is not compatible with GNU libc.
 AC_DEFUN([gl_FUNC_MALLOC_GNU],
 [
   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
-  dnl _AC_FUNC_MALLOC_IF is defined in Autoconf.
-  _AC_FUNC_MALLOC_IF(
-    [AC_DEFINE([HAVE_MALLOC_GNU], [1],
-               [Define to 1 if your system has a GNU libc compatible 'malloc'
-                function, and to 0 otherwise.])],
-    [AC_DEFINE([HAVE_MALLOC_GNU], [0])
-     REPLACE_MALLOC=1
+  AC_REQUIRE([gl_FUNC_MALLOC_POSIX])
+  REPLACE_MALLOC_FOR_MALLOC_GNU="$REPLACE_MALLOC_FOR_MALLOC_POSIX"
+  if test $REPLACE_MALLOC_FOR_MALLOC_GNU = 0; then
+    _AC_FUNC_MALLOC_IF([], [REPLACE_MALLOC_FOR_MALLOC_GNU=1])
+  fi
+])
+
+# gl_FUNC_MALLOC_PTRDIFF
+# ----------------------
+# Test whether malloc (N) reliably fails when N exceeds PTRDIFF_MAX,
+# and replace malloc otherwise.
+AC_DEFUN([gl_FUNC_MALLOC_PTRDIFF],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([gl_CHECK_MALLOC_PTRDIFF])
+  test "$gl_cv_malloc_ptrdiff" = yes || REPLACE_MALLOC_FOR_MALLOC_POSIX=1
+])
+
+# Test whether malloc, realloc, calloc refuse to create objects
+# larger than what can be expressed in ptrdiff_t.
+# Set gl_cv_func_malloc_gnu to yes or no accordingly.
+AC_DEFUN([gl_CHECK_MALLOC_PTRDIFF],
+[
+  AC_CACHE_CHECK([whether malloc is ptrdiff_t safe],
+    [gl_cv_malloc_ptrdiff],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <stdint.h>
+          ]],
+          [[/* 64-bit ptrdiff_t is so wide that no practical platform
+               can exceed it.  */
+            #define WIDE_PTRDIFF (PTRDIFF_MAX >> 31 >> 31 != 0)
+
+            /* On rare machines where size_t fits in ptrdiff_t there
+               is no problem.  */
+            #define NARROW_SIZE (SIZE_MAX <= PTRDIFF_MAX)
+
+            /* glibc 2.30 and later malloc refuses to exceed ptrdiff_t
+               bounds even on 32-bit platforms.  We don't know which
+               non-glibc systems are safe.  */
+            #define KNOWN_SAFE (2 < __GLIBC__ + (30 <= __GLIBC_MINOR__))
+
+            #if WIDE_PTRDIFF || NARROW_SIZE || KNOWN_SAFE
+              return 0;
+            #else
+              #error "malloc might not be ptrdiff_t safe"
+              syntax error
+            #endif
+          ]])],
+       [gl_cv_malloc_ptrdiff=yes],
+       [gl_cv_malloc_ptrdiff=no])
     ])
 ])
 
 # gl_FUNC_MALLOC_POSIX
 # --------------------
 # Test whether 'malloc' is POSIX compliant (sets errno to ENOMEM when it
-# fails), and replace malloc if it is not.
+# fails, and doesn't mess up with ptrdiff_t overflow), and replace
+# malloc if it is not.
 AC_DEFUN([gl_FUNC_MALLOC_POSIX],
 [
   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_MALLOC_PTRDIFF])
   AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
-  if test $gl_cv_func_malloc_posix = yes; then
+  if test "$gl_cv_func_malloc_posix" = yes; then
     AC_DEFINE([HAVE_MALLOC_POSIX], [1],
-      [Define if the 'malloc' function is POSIX compliant.])
+      [Define if malloc, realloc, and calloc set errno on allocation failure.])
   else
-    REPLACE_MALLOC=1
+    REPLACE_MALLOC_FOR_MALLOC_POSIX=1
   fi
 ])
 
-# Test whether malloc, realloc, calloc are POSIX compliant,
+# Test whether malloc, realloc, calloc set errno to ENOMEM on failure.
 # Set gl_cv_func_malloc_posix to yes or no accordingly.
 AC_DEFUN([gl_CHECK_MALLOC_POSIX],
 [
-  AC_CACHE_CHECK([whether malloc, realloc, calloc are POSIX compliant],
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CACHE_CHECK([whether malloc, realloc, calloc set errno on failure],
     [gl_cv_func_malloc_posix],
     [
       dnl It is too dangerous to try to allocate a large amount of memory:
       dnl some systems go to their knees when you do that. So assume that
-      dnl all Unix implementations of the function are POSIX compliant.
-      AC_COMPILE_IFELSE(
-        [AC_LANG_PROGRAM(
-           [[]],
-           [[#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
-             choke me
-             #endif
-            ]])],
-        [gl_cv_func_malloc_posix=yes],
-        [gl_cv_func_malloc_posix=no])
+      dnl all Unix implementations of the function set errno on failure,
+      dnl except on those platforms where we have seen 'test-malloc-gnu',
+      dnl 'test-realloc-gnu', 'test-calloc-gnu' fail.
+      case "$host_os" in
+        mingw*)
+          gl_cv_func_malloc_posix=no ;;
+        irix* | solaris*)
+          dnl On IRIX 6.5, the three functions return NULL with errno unset
+          dnl when the argument is larger than PTRDIFF_MAX.
+          dnl On Solaris 11.3, the three functions return NULL with errno set
+          dnl to EAGAIN, not ENOMEM, when the argument is larger than
+          dnl PTRDIFF_MAX.
+          dnl Here is a test program:
+m4_divert_push([KILL])
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#define ptrdiff_t long
+#ifndef PTRDIFF_MAX
+# define PTRDIFF_MAX ((ptrdiff_t) ((1UL << (8 * sizeof (ptrdiff_t) - 1)) - 1))
+#endif
+
+int main ()
+{
+  void *p;
+
+  fprintf (stderr, "PTRDIFF_MAX = %lu\n", (unsigned long) PTRDIFF_MAX);
+
+  errno = 0;
+  p = malloc ((unsigned long) PTRDIFF_MAX + 1);
+  fprintf (stderr, "p=%p errno=%d\n", p, errno);
+
+  errno = 0;
+  p = calloc (PTRDIFF_MAX / 2 + 1, 2);
+  fprintf (stderr, "p=%p errno=%d\n", p, errno);
+
+  errno = 0;
+  p = realloc (NULL, (unsigned long) PTRDIFF_MAX + 1);
+  fprintf (stderr, "p=%p errno=%d\n", p, errno);
+
+  return 0;
+}
+m4_divert_pop([KILL])
+          gl_cv_func_malloc_posix=no ;;
+        *)
+          gl_cv_func_malloc_posix=yes ;;
+      esac
     ])
 ])
diff --git a/gl/m4/malloca.m4 b/gl/m4/malloca.m4
index 791ce10d..1d777ebe 100644
--- a/gl/m4/malloca.m4
+++ b/gl/m4/malloca.m4
@@ -1,5 +1,5 @@
-# malloca.m4 serial 1
-dnl Copyright (C) 2003-2004, 2006-2007, 2009-2013 Free Software Foundation,
+# malloca.m4 serial 2
+dnl Copyright (C) 2003-2004, 2006-2007, 2009-2023 Free Software Foundation,
 dnl Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,5 +11,4 @@ AC_DEFUN([gl_MALLOCA],
   dnl @ALLOCA@ and @LTALLOCA@.
   dnl gl_FUNC_ALLOCA   dnl Already brought in by the module dependencies.
   AC_REQUIRE([gl_EEMALLOC])
-  AC_REQUIRE([AC_TYPE_LONG_LONG_INT])
 ])
diff --git a/gl/m4/math_h.m4 b/gl/m4/math_h.m4
index bf0845fd..d2e90ff1 100644
--- a/gl/m4/math_h.m4
+++ b/gl/m4/math_h.m4
@@ -1,16 +1,16 @@
-# math_h.m4 serial 114
-dnl Copyright (C) 2007-2013 Free Software Foundation, Inc.
+# math_h.m4 serial 125
+dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-AC_DEFUN([gl_MATH_H],
+AC_DEFUN_ONCE([gl_MATH_H],
 [
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
   gl_CHECK_NEXT_HEADERS([math.h])
 
   AC_CACHE_CHECK([whether NAN macro works], [gl_cv_header_math_nan_works],
-    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@%:@include <math.h>]],
+    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <math.h>]],
       [[/* Solaris 10 has a broken definition of NAN.  Other platforms
         fail to provide NAN, or provide it only in C99 mode; this
         test only needs to fail when NAN is provided but wrong.  */
@@ -25,7 +25,7 @@ AC_DEFUN([gl_MATH_H],
     REPLACE_NAN=1
   fi
   AC_CACHE_CHECK([whether HUGE_VAL works], [gl_cv_header_math_huge_val_works],
-    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@%:@include <math.h>]],
+    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <math.h>]],
       [[/* Solaris 10 has a broken definition of HUGE_VAL.  */
          double d = HUGE_VAL;
          return d == 0;]])],
@@ -53,272 +53,310 @@ AC_DEFUN([gl_MATH_H],
      tanf tanl tanhf trunc truncf truncl])
 ])
 
+# gl_MATH_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_MATH_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_MATH_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_MATH_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_MATH_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ACOSF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ACOSL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ASINF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ASINL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ATANF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ATANL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ATAN2F])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CBRT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CBRTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CBRTL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CEIL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CEILF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CEILL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_COPYSIGN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_COPYSIGNF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_COPYSIGNL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_COSF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_COSL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_COSHF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXPF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXPL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXP2])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXP2F])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXP2L])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXPM1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXPM1F])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXPM1L])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FABSF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FABSL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FLOOR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FLOORF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FLOORL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FMA])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FMAF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FMAL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FMOD])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FMODF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FMODL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FREXPF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FREXP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FREXPL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_HYPOT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_HYPOTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_HYPOTL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ILOGB])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ILOGBF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ILOGBL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISFINITE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISINF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNAN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNANF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNAND])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNANL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LDEXPF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LDEXPL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOG])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOGF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOGL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOG10])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOG10F])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOG10L])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOG1P])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOG1PF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOG1PL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOG2])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOG2F])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOG2L])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOGB])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOGBF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOGBL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MODF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MODFF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MODFL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_POWF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_REMAINDER])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_REMAINDERF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_REMAINDERL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RINT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RINTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RINTL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ROUND])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ROUNDF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ROUNDL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SIGNBIT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SINF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SINL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SINHF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SQRTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SQRTL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TANF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TANL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TANHF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TRUNC])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TRUNCF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TRUNCL])
+    dnl Support Microsoft deprecated alias function names by default.
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_J0], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_J1], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_JN], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_Y0], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_Y1], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_YN], [1])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_MATH_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_MATH_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_MATH_H_DEFAULTS],
 [
-  GNULIB_ACOSF=0;      AC_SUBST([GNULIB_ACOSF])
-  GNULIB_ACOSL=0;      AC_SUBST([GNULIB_ACOSL])
-  GNULIB_ASINF=0;      AC_SUBST([GNULIB_ASINF])
-  GNULIB_ASINL=0;      AC_SUBST([GNULIB_ASINL])
-  GNULIB_ATANF=0;      AC_SUBST([GNULIB_ATANF])
-  GNULIB_ATANL=0;      AC_SUBST([GNULIB_ATANL])
-  GNULIB_ATAN2F=0;     AC_SUBST([GNULIB_ATAN2F])
-  GNULIB_CBRT=0;       AC_SUBST([GNULIB_CBRT])
-  GNULIB_CBRTF=0;      AC_SUBST([GNULIB_CBRTF])
-  GNULIB_CBRTL=0;      AC_SUBST([GNULIB_CBRTL])
-  GNULIB_CEIL=0;       AC_SUBST([GNULIB_CEIL])
-  GNULIB_CEILF=0;      AC_SUBST([GNULIB_CEILF])
-  GNULIB_CEILL=0;      AC_SUBST([GNULIB_CEILL])
-  GNULIB_COPYSIGN=0;   AC_SUBST([GNULIB_COPYSIGN])
-  GNULIB_COPYSIGNF=0;  AC_SUBST([GNULIB_COPYSIGNF])
-  GNULIB_COPYSIGNL=0;  AC_SUBST([GNULIB_COPYSIGNL])
-  GNULIB_COSF=0;       AC_SUBST([GNULIB_COSF])
-  GNULIB_COSL=0;       AC_SUBST([GNULIB_COSL])
-  GNULIB_COSHF=0;      AC_SUBST([GNULIB_COSHF])
-  GNULIB_EXPF=0;       AC_SUBST([GNULIB_EXPF])
-  GNULIB_EXPL=0;       AC_SUBST([GNULIB_EXPL])
-  GNULIB_EXP2=0;       AC_SUBST([GNULIB_EXP2])
-  GNULIB_EXP2F=0;      AC_SUBST([GNULIB_EXP2F])
-  GNULIB_EXP2L=0;      AC_SUBST([GNULIB_EXP2L])
-  GNULIB_EXPM1=0;      AC_SUBST([GNULIB_EXPM1])
-  GNULIB_EXPM1F=0;     AC_SUBST([GNULIB_EXPM1F])
-  GNULIB_EXPM1L=0;     AC_SUBST([GNULIB_EXPM1L])
-  GNULIB_FABSF=0;      AC_SUBST([GNULIB_FABSF])
-  GNULIB_FABSL=0;      AC_SUBST([GNULIB_FABSL])
-  GNULIB_FLOOR=0;      AC_SUBST([GNULIB_FLOOR])
-  GNULIB_FLOORF=0;     AC_SUBST([GNULIB_FLOORF])
-  GNULIB_FLOORL=0;     AC_SUBST([GNULIB_FLOORL])
-  GNULIB_FMA=0;        AC_SUBST([GNULIB_FMA])
-  GNULIB_FMAF=0;       AC_SUBST([GNULIB_FMAF])
-  GNULIB_FMAL=0;       AC_SUBST([GNULIB_FMAL])
-  GNULIB_FMOD=0;       AC_SUBST([GNULIB_FMOD])
-  GNULIB_FMODF=0;      AC_SUBST([GNULIB_FMODF])
-  GNULIB_FMODL=0;      AC_SUBST([GNULIB_FMODL])
-  GNULIB_FREXPF=0;     AC_SUBST([GNULIB_FREXPF])
-  GNULIB_FREXP=0;      AC_SUBST([GNULIB_FREXP])
-  GNULIB_FREXPL=0;     AC_SUBST([GNULIB_FREXPL])
-  GNULIB_HYPOT=0;      AC_SUBST([GNULIB_HYPOT])
-  GNULIB_HYPOTF=0;     AC_SUBST([GNULIB_HYPOTF])
-  GNULIB_HYPOTL=0;     AC_SUBST([GNULIB_HYPOTL])
-  GNULIB_ILOGB=0;      AC_SUBST([GNULIB_ILOGB])
-  GNULIB_ILOGBF=0;     AC_SUBST([GNULIB_ILOGBF])
-  GNULIB_ILOGBL=0;     AC_SUBST([GNULIB_ILOGBL])
-  GNULIB_ISFINITE=0;   AC_SUBST([GNULIB_ISFINITE])
-  GNULIB_ISINF=0;      AC_SUBST([GNULIB_ISINF])
-  GNULIB_ISNAN=0;      AC_SUBST([GNULIB_ISNAN])
-  GNULIB_ISNANF=0;     AC_SUBST([GNULIB_ISNANF])
-  GNULIB_ISNAND=0;     AC_SUBST([GNULIB_ISNAND])
-  GNULIB_ISNANL=0;     AC_SUBST([GNULIB_ISNANL])
-  GNULIB_LDEXPF=0;     AC_SUBST([GNULIB_LDEXPF])
-  GNULIB_LDEXPL=0;     AC_SUBST([GNULIB_LDEXPL])
-  GNULIB_LOG=0;        AC_SUBST([GNULIB_LOG])
-  GNULIB_LOGF=0;       AC_SUBST([GNULIB_LOGF])
-  GNULIB_LOGL=0;       AC_SUBST([GNULIB_LOGL])
-  GNULIB_LOG10=0;      AC_SUBST([GNULIB_LOG10])
-  GNULIB_LOG10F=0;     AC_SUBST([GNULIB_LOG10F])
-  GNULIB_LOG10L=0;     AC_SUBST([GNULIB_LOG10L])
-  GNULIB_LOG1P=0;      AC_SUBST([GNULIB_LOG1P])
-  GNULIB_LOG1PF=0;     AC_SUBST([GNULIB_LOG1PF])
-  GNULIB_LOG1PL=0;     AC_SUBST([GNULIB_LOG1PL])
-  GNULIB_LOG2=0;       AC_SUBST([GNULIB_LOG2])
-  GNULIB_LOG2F=0;      AC_SUBST([GNULIB_LOG2F])
-  GNULIB_LOG2L=0;      AC_SUBST([GNULIB_LOG2L])
-  GNULIB_LOGB=0;       AC_SUBST([GNULIB_LOGB])
-  GNULIB_LOGBF=0;      AC_SUBST([GNULIB_LOGBF])
-  GNULIB_LOGBL=0;      AC_SUBST([GNULIB_LOGBL])
-  GNULIB_MODF=0;       AC_SUBST([GNULIB_MODF])
-  GNULIB_MODFF=0;      AC_SUBST([GNULIB_MODFF])
-  GNULIB_MODFL=0;      AC_SUBST([GNULIB_MODFL])
-  GNULIB_POWF=0;       AC_SUBST([GNULIB_POWF])
-  GNULIB_REMAINDER=0;  AC_SUBST([GNULIB_REMAINDER])
-  GNULIB_REMAINDERF=0; AC_SUBST([GNULIB_REMAINDERF])
-  GNULIB_REMAINDERL=0; AC_SUBST([GNULIB_REMAINDERL])
-  GNULIB_RINT=0;       AC_SUBST([GNULIB_RINT])
-  GNULIB_RINTF=0;      AC_SUBST([GNULIB_RINTF])
-  GNULIB_RINTL=0;      AC_SUBST([GNULIB_RINTL])
-  GNULIB_ROUND=0;      AC_SUBST([GNULIB_ROUND])
-  GNULIB_ROUNDF=0;     AC_SUBST([GNULIB_ROUNDF])
-  GNULIB_ROUNDL=0;     AC_SUBST([GNULIB_ROUNDL])
-  GNULIB_SIGNBIT=0;    AC_SUBST([GNULIB_SIGNBIT])
-  GNULIB_SINF=0;       AC_SUBST([GNULIB_SINF])
-  GNULIB_SINL=0;       AC_SUBST([GNULIB_SINL])
-  GNULIB_SINHF=0;      AC_SUBST([GNULIB_SINHF])
-  GNULIB_SQRTF=0;      AC_SUBST([GNULIB_SQRTF])
-  GNULIB_SQRTL=0;      AC_SUBST([GNULIB_SQRTL])
-  GNULIB_TANF=0;       AC_SUBST([GNULIB_TANF])
-  GNULIB_TANL=0;       AC_SUBST([GNULIB_TANL])
-  GNULIB_TANHF=0;      AC_SUBST([GNULIB_TANHF])
-  GNULIB_TRUNC=0;      AC_SUBST([GNULIB_TRUNC])
-  GNULIB_TRUNCF=0;     AC_SUBST([GNULIB_TRUNCF])
-  GNULIB_TRUNCL=0;     AC_SUBST([GNULIB_TRUNCL])
   dnl Assume proper GNU behavior unless another module says otherwise.
-  HAVE_ACOSF=1;                AC_SUBST([HAVE_ACOSF])
-  HAVE_ACOSL=1;                AC_SUBST([HAVE_ACOSL])
-  HAVE_ASINF=1;                AC_SUBST([HAVE_ASINF])
-  HAVE_ASINL=1;                AC_SUBST([HAVE_ASINL])
-  HAVE_ATANF=1;                AC_SUBST([HAVE_ATANF])
-  HAVE_ATANL=1;                AC_SUBST([HAVE_ATANL])
-  HAVE_ATAN2F=1;               AC_SUBST([HAVE_ATAN2F])
-  HAVE_CBRT=1;                 AC_SUBST([HAVE_CBRT])
-  HAVE_CBRTF=1;                AC_SUBST([HAVE_CBRTF])
-  HAVE_CBRTL=1;                AC_SUBST([HAVE_CBRTL])
-  HAVE_COPYSIGN=1;             AC_SUBST([HAVE_COPYSIGN])
-  HAVE_COPYSIGNL=1;            AC_SUBST([HAVE_COPYSIGNL])
-  HAVE_COSF=1;                 AC_SUBST([HAVE_COSF])
-  HAVE_COSL=1;                 AC_SUBST([HAVE_COSL])
-  HAVE_COSHF=1;                AC_SUBST([HAVE_COSHF])
-  HAVE_EXPF=1;                 AC_SUBST([HAVE_EXPF])
-  HAVE_EXPL=1;                 AC_SUBST([HAVE_EXPL])
-  HAVE_EXPM1=1;                AC_SUBST([HAVE_EXPM1])
-  HAVE_EXPM1F=1;               AC_SUBST([HAVE_EXPM1F])
-  HAVE_FABSF=1;                AC_SUBST([HAVE_FABSF])
-  HAVE_FABSL=1;                AC_SUBST([HAVE_FABSL])
-  HAVE_FMA=1;                  AC_SUBST([HAVE_FMA])
-  HAVE_FMAF=1;                 AC_SUBST([HAVE_FMAF])
-  HAVE_FMAL=1;                 AC_SUBST([HAVE_FMAL])
-  HAVE_FMODF=1;                AC_SUBST([HAVE_FMODF])
-  HAVE_FMODL=1;                AC_SUBST([HAVE_FMODL])
-  HAVE_FREXPF=1;               AC_SUBST([HAVE_FREXPF])
-  HAVE_HYPOTF=1;               AC_SUBST([HAVE_HYPOTF])
-  HAVE_HYPOTL=1;               AC_SUBST([HAVE_HYPOTL])
-  HAVE_ILOGB=1;                AC_SUBST([HAVE_ILOGB])
-  HAVE_ILOGBF=1;               AC_SUBST([HAVE_ILOGBF])
-  HAVE_ILOGBL=1;               AC_SUBST([HAVE_ILOGBL])
-  HAVE_ISNANF=1;               AC_SUBST([HAVE_ISNANF])
-  HAVE_ISNAND=1;               AC_SUBST([HAVE_ISNAND])
-  HAVE_ISNANL=1;               AC_SUBST([HAVE_ISNANL])
-  HAVE_LDEXPF=1;               AC_SUBST([HAVE_LDEXPF])
-  HAVE_LOGF=1;                 AC_SUBST([HAVE_LOGF])
-  HAVE_LOGL=1;                 AC_SUBST([HAVE_LOGL])
-  HAVE_LOG10F=1;               AC_SUBST([HAVE_LOG10F])
-  HAVE_LOG10L=1;               AC_SUBST([HAVE_LOG10L])
-  HAVE_LOG1P=1;                AC_SUBST([HAVE_LOG1P])
-  HAVE_LOG1PF=1;               AC_SUBST([HAVE_LOG1PF])
-  HAVE_LOG1PL=1;               AC_SUBST([HAVE_LOG1PL])
-  HAVE_LOGBF=1;                AC_SUBST([HAVE_LOGBF])
-  HAVE_LOGBL=1;                AC_SUBST([HAVE_LOGBL])
-  HAVE_MODFF=1;                AC_SUBST([HAVE_MODFF])
-  HAVE_MODFL=1;                AC_SUBST([HAVE_MODFL])
-  HAVE_POWF=1;                 AC_SUBST([HAVE_POWF])
-  HAVE_REMAINDER=1;            AC_SUBST([HAVE_REMAINDER])
-  HAVE_REMAINDERF=1;           AC_SUBST([HAVE_REMAINDERF])
-  HAVE_RINT=1;                 AC_SUBST([HAVE_RINT])
-  HAVE_RINTL=1;                AC_SUBST([HAVE_RINTL])
-  HAVE_SINF=1;                 AC_SUBST([HAVE_SINF])
-  HAVE_SINL=1;                 AC_SUBST([HAVE_SINL])
-  HAVE_SINHF=1;                AC_SUBST([HAVE_SINHF])
-  HAVE_SQRTF=1;                AC_SUBST([HAVE_SQRTF])
-  HAVE_SQRTL=1;                AC_SUBST([HAVE_SQRTL])
-  HAVE_TANF=1;                 AC_SUBST([HAVE_TANF])
-  HAVE_TANL=1;                 AC_SUBST([HAVE_TANL])
-  HAVE_TANHF=1;                AC_SUBST([HAVE_TANHF])
-  HAVE_DECL_ACOSL=1;           AC_SUBST([HAVE_DECL_ACOSL])
-  HAVE_DECL_ASINL=1;           AC_SUBST([HAVE_DECL_ASINL])
-  HAVE_DECL_ATANL=1;           AC_SUBST([HAVE_DECL_ATANL])
-  HAVE_DECL_CBRTF=1;           AC_SUBST([HAVE_DECL_CBRTF])
-  HAVE_DECL_CBRTL=1;           AC_SUBST([HAVE_DECL_CBRTL])
-  HAVE_DECL_CEILF=1;           AC_SUBST([HAVE_DECL_CEILF])
-  HAVE_DECL_CEILL=1;           AC_SUBST([HAVE_DECL_CEILL])
-  HAVE_DECL_COPYSIGNF=1;       AC_SUBST([HAVE_DECL_COPYSIGNF])
-  HAVE_DECL_COSL=1;            AC_SUBST([HAVE_DECL_COSL])
-  HAVE_DECL_EXPL=1;            AC_SUBST([HAVE_DECL_EXPL])
-  HAVE_DECL_EXP2=1;            AC_SUBST([HAVE_DECL_EXP2])
-  HAVE_DECL_EXP2F=1;           AC_SUBST([HAVE_DECL_EXP2F])
-  HAVE_DECL_EXP2L=1;           AC_SUBST([HAVE_DECL_EXP2L])
-  HAVE_DECL_EXPM1L=1;          AC_SUBST([HAVE_DECL_EXPM1L])
-  HAVE_DECL_FLOORF=1;          AC_SUBST([HAVE_DECL_FLOORF])
-  HAVE_DECL_FLOORL=1;          AC_SUBST([HAVE_DECL_FLOORL])
-  HAVE_DECL_FREXPL=1;          AC_SUBST([HAVE_DECL_FREXPL])
-  HAVE_DECL_LDEXPL=1;          AC_SUBST([HAVE_DECL_LDEXPL])
-  HAVE_DECL_LOGL=1;            AC_SUBST([HAVE_DECL_LOGL])
-  HAVE_DECL_LOG10L=1;          AC_SUBST([HAVE_DECL_LOG10L])
-  HAVE_DECL_LOG2=1;            AC_SUBST([HAVE_DECL_LOG2])
-  HAVE_DECL_LOG2F=1;           AC_SUBST([HAVE_DECL_LOG2F])
-  HAVE_DECL_LOG2L=1;           AC_SUBST([HAVE_DECL_LOG2L])
-  HAVE_DECL_LOGB=1;            AC_SUBST([HAVE_DECL_LOGB])
-  HAVE_DECL_REMAINDER=1;       AC_SUBST([HAVE_DECL_REMAINDER])
-  HAVE_DECL_REMAINDERL=1;      AC_SUBST([HAVE_DECL_REMAINDERL])
-  HAVE_DECL_RINTF=1;           AC_SUBST([HAVE_DECL_RINTF])
-  HAVE_DECL_ROUND=1;           AC_SUBST([HAVE_DECL_ROUND])
-  HAVE_DECL_ROUNDF=1;          AC_SUBST([HAVE_DECL_ROUNDF])
-  HAVE_DECL_ROUNDL=1;          AC_SUBST([HAVE_DECL_ROUNDL])
-  HAVE_DECL_SINL=1;            AC_SUBST([HAVE_DECL_SINL])
-  HAVE_DECL_SQRTL=1;           AC_SUBST([HAVE_DECL_SQRTL])
-  HAVE_DECL_TANL=1;            AC_SUBST([HAVE_DECL_TANL])
-  HAVE_DECL_TRUNC=1;           AC_SUBST([HAVE_DECL_TRUNC])
-  HAVE_DECL_TRUNCF=1;          AC_SUBST([HAVE_DECL_TRUNCF])
-  HAVE_DECL_TRUNCL=1;          AC_SUBST([HAVE_DECL_TRUNCL])
-  REPLACE_CBRTF=0;             AC_SUBST([REPLACE_CBRTF])
-  REPLACE_CBRTL=0;             AC_SUBST([REPLACE_CBRTL])
-  REPLACE_CEIL=0;              AC_SUBST([REPLACE_CEIL])
-  REPLACE_CEILF=0;             AC_SUBST([REPLACE_CEILF])
-  REPLACE_CEILL=0;             AC_SUBST([REPLACE_CEILL])
-  REPLACE_EXPM1=0;             AC_SUBST([REPLACE_EXPM1])
-  REPLACE_EXPM1F=0;            AC_SUBST([REPLACE_EXPM1F])
-  REPLACE_EXP2=0;              AC_SUBST([REPLACE_EXP2])
-  REPLACE_EXP2L=0;             AC_SUBST([REPLACE_EXP2L])
-  REPLACE_FABSL=0;             AC_SUBST([REPLACE_FABSL])
-  REPLACE_FLOOR=0;             AC_SUBST([REPLACE_FLOOR])
-  REPLACE_FLOORF=0;            AC_SUBST([REPLACE_FLOORF])
-  REPLACE_FLOORL=0;            AC_SUBST([REPLACE_FLOORL])
-  REPLACE_FMA=0;               AC_SUBST([REPLACE_FMA])
-  REPLACE_FMAF=0;              AC_SUBST([REPLACE_FMAF])
-  REPLACE_FMAL=0;              AC_SUBST([REPLACE_FMAL])
-  REPLACE_FMOD=0;              AC_SUBST([REPLACE_FMOD])
-  REPLACE_FMODF=0;             AC_SUBST([REPLACE_FMODF])
-  REPLACE_FMODL=0;             AC_SUBST([REPLACE_FMODL])
-  REPLACE_FREXPF=0;            AC_SUBST([REPLACE_FREXPF])
-  REPLACE_FREXP=0;             AC_SUBST([REPLACE_FREXP])
-  REPLACE_FREXPL=0;            AC_SUBST([REPLACE_FREXPL])
-  REPLACE_HUGE_VAL=0;          AC_SUBST([REPLACE_HUGE_VAL])
-  REPLACE_HYPOT=0;             AC_SUBST([REPLACE_HYPOT])
-  REPLACE_HYPOTF=0;            AC_SUBST([REPLACE_HYPOTF])
-  REPLACE_HYPOTL=0;            AC_SUBST([REPLACE_HYPOTL])
-  REPLACE_ILOGB=0;             AC_SUBST([REPLACE_ILOGB])
-  REPLACE_ILOGBF=0;            AC_SUBST([REPLACE_ILOGBF])
-  REPLACE_ISFINITE=0;          AC_SUBST([REPLACE_ISFINITE])
-  REPLACE_ISINF=0;             AC_SUBST([REPLACE_ISINF])
-  REPLACE_ISNAN=0;             AC_SUBST([REPLACE_ISNAN])
-  REPLACE_LDEXPL=0;            AC_SUBST([REPLACE_LDEXPL])
-  REPLACE_LOG=0;               AC_SUBST([REPLACE_LOG])
-  REPLACE_LOGF=0;              AC_SUBST([REPLACE_LOGF])
-  REPLACE_LOGL=0;              AC_SUBST([REPLACE_LOGL])
-  REPLACE_LOG10=0;             AC_SUBST([REPLACE_LOG10])
-  REPLACE_LOG10F=0;            AC_SUBST([REPLACE_LOG10F])
-  REPLACE_LOG10L=0;            AC_SUBST([REPLACE_LOG10L])
-  REPLACE_LOG1P=0;             AC_SUBST([REPLACE_LOG1P])
-  REPLACE_LOG1PF=0;            AC_SUBST([REPLACE_LOG1PF])
-  REPLACE_LOG1PL=0;            AC_SUBST([REPLACE_LOG1PL])
-  REPLACE_LOG2=0;              AC_SUBST([REPLACE_LOG2])
-  REPLACE_LOG2F=0;             AC_SUBST([REPLACE_LOG2F])
-  REPLACE_LOG2L=0;             AC_SUBST([REPLACE_LOG2L])
-  REPLACE_LOGB=0;              AC_SUBST([REPLACE_LOGB])
-  REPLACE_LOGBF=0;             AC_SUBST([REPLACE_LOGBF])
-  REPLACE_LOGBL=0;             AC_SUBST([REPLACE_LOGBL])
-  REPLACE_MODF=0;              AC_SUBST([REPLACE_MODF])
-  REPLACE_MODFF=0;             AC_SUBST([REPLACE_MODFF])
-  REPLACE_MODFL=0;             AC_SUBST([REPLACE_MODFL])
-  REPLACE_NAN=0;               AC_SUBST([REPLACE_NAN])
-  REPLACE_REMAINDER=0;         AC_SUBST([REPLACE_REMAINDER])
-  REPLACE_REMAINDERF=0;        AC_SUBST([REPLACE_REMAINDERF])
-  REPLACE_REMAINDERL=0;        AC_SUBST([REPLACE_REMAINDERL])
-  REPLACE_ROUND=0;             AC_SUBST([REPLACE_ROUND])
-  REPLACE_ROUNDF=0;            AC_SUBST([REPLACE_ROUNDF])
-  REPLACE_ROUNDL=0;            AC_SUBST([REPLACE_ROUNDL])
-  REPLACE_SIGNBIT=0;           AC_SUBST([REPLACE_SIGNBIT])
-  REPLACE_SIGNBIT_USING_GCC=0; AC_SUBST([REPLACE_SIGNBIT_USING_GCC])
-  REPLACE_SQRTL=0;             AC_SUBST([REPLACE_SQRTL])
-  REPLACE_TRUNC=0;             AC_SUBST([REPLACE_TRUNC])
-  REPLACE_TRUNCF=0;            AC_SUBST([REPLACE_TRUNCF])
-  REPLACE_TRUNCL=0;            AC_SUBST([REPLACE_TRUNCL])
+  HAVE_ACOSF=1;                     AC_SUBST([HAVE_ACOSF])
+  HAVE_ACOSL=1;                     AC_SUBST([HAVE_ACOSL])
+  HAVE_ASINF=1;                     AC_SUBST([HAVE_ASINF])
+  HAVE_ASINL=1;                     AC_SUBST([HAVE_ASINL])
+  HAVE_ATANF=1;                     AC_SUBST([HAVE_ATANF])
+  HAVE_ATANL=1;                     AC_SUBST([HAVE_ATANL])
+  HAVE_ATAN2F=1;                    AC_SUBST([HAVE_ATAN2F])
+  HAVE_CBRT=1;                      AC_SUBST([HAVE_CBRT])
+  HAVE_CBRTF=1;                     AC_SUBST([HAVE_CBRTF])
+  HAVE_CBRTL=1;                     AC_SUBST([HAVE_CBRTL])
+  HAVE_COPYSIGN=1;                  AC_SUBST([HAVE_COPYSIGN])
+  HAVE_COPYSIGNL=1;                 AC_SUBST([HAVE_COPYSIGNL])
+  HAVE_COSF=1;                      AC_SUBST([HAVE_COSF])
+  HAVE_COSL=1;                      AC_SUBST([HAVE_COSL])
+  HAVE_COSHF=1;                     AC_SUBST([HAVE_COSHF])
+  HAVE_EXPF=1;                      AC_SUBST([HAVE_EXPF])
+  HAVE_EXPL=1;                      AC_SUBST([HAVE_EXPL])
+  HAVE_EXPM1=1;                     AC_SUBST([HAVE_EXPM1])
+  HAVE_EXPM1F=1;                    AC_SUBST([HAVE_EXPM1F])
+  HAVE_FABSF=1;                     AC_SUBST([HAVE_FABSF])
+  HAVE_FABSL=1;                     AC_SUBST([HAVE_FABSL])
+  HAVE_FMA=1;                       AC_SUBST([HAVE_FMA])
+  HAVE_FMAF=1;                      AC_SUBST([HAVE_FMAF])
+  HAVE_FMAL=1;                      AC_SUBST([HAVE_FMAL])
+  HAVE_FMODF=1;                     AC_SUBST([HAVE_FMODF])
+  HAVE_FMODL=1;                     AC_SUBST([HAVE_FMODL])
+  HAVE_FREXPF=1;                    AC_SUBST([HAVE_FREXPF])
+  HAVE_HYPOTF=1;                    AC_SUBST([HAVE_HYPOTF])
+  HAVE_HYPOTL=1;                    AC_SUBST([HAVE_HYPOTL])
+  HAVE_ILOGB=1;                     AC_SUBST([HAVE_ILOGB])
+  HAVE_ILOGBF=1;                    AC_SUBST([HAVE_ILOGBF])
+  HAVE_ILOGBL=1;                    AC_SUBST([HAVE_ILOGBL])
+  HAVE_ISNANF=1;                    AC_SUBST([HAVE_ISNANF])
+  HAVE_ISNAND=1;                    AC_SUBST([HAVE_ISNAND])
+  HAVE_ISNANL=1;                    AC_SUBST([HAVE_ISNANL])
+  HAVE_LDEXPF=1;                    AC_SUBST([HAVE_LDEXPF])
+  HAVE_LOGF=1;                      AC_SUBST([HAVE_LOGF])
+  HAVE_LOGL=1;                      AC_SUBST([HAVE_LOGL])
+  HAVE_LOG10F=1;                    AC_SUBST([HAVE_LOG10F])
+  HAVE_LOG10L=1;                    AC_SUBST([HAVE_LOG10L])
+  HAVE_LOG1P=1;                     AC_SUBST([HAVE_LOG1P])
+  HAVE_LOG1PF=1;                    AC_SUBST([HAVE_LOG1PF])
+  HAVE_LOG1PL=1;                    AC_SUBST([HAVE_LOG1PL])
+  HAVE_LOGBF=1;                     AC_SUBST([HAVE_LOGBF])
+  HAVE_LOGBL=1;                     AC_SUBST([HAVE_LOGBL])
+  HAVE_MODFF=1;                     AC_SUBST([HAVE_MODFF])
+  HAVE_MODFL=1;                     AC_SUBST([HAVE_MODFL])
+  HAVE_POWF=1;                      AC_SUBST([HAVE_POWF])
+  HAVE_REMAINDER=1;                 AC_SUBST([HAVE_REMAINDER])
+  HAVE_REMAINDERF=1;                AC_SUBST([HAVE_REMAINDERF])
+  HAVE_RINT=1;                      AC_SUBST([HAVE_RINT])
+  HAVE_RINTL=1;                     AC_SUBST([HAVE_RINTL])
+  HAVE_SINF=1;                      AC_SUBST([HAVE_SINF])
+  HAVE_SINL=1;                      AC_SUBST([HAVE_SINL])
+  HAVE_SINHF=1;                     AC_SUBST([HAVE_SINHF])
+  HAVE_SQRTF=1;                     AC_SUBST([HAVE_SQRTF])
+  HAVE_SQRTL=1;                     AC_SUBST([HAVE_SQRTL])
+  HAVE_TANF=1;                      AC_SUBST([HAVE_TANF])
+  HAVE_TANL=1;                      AC_SUBST([HAVE_TANL])
+  HAVE_TANHF=1;                     AC_SUBST([HAVE_TANHF])
+  HAVE_DECL_ACOSL=1;                AC_SUBST([HAVE_DECL_ACOSL])
+  HAVE_DECL_ASINL=1;                AC_SUBST([HAVE_DECL_ASINL])
+  HAVE_DECL_ATANL=1;                AC_SUBST([HAVE_DECL_ATANL])
+  HAVE_DECL_CBRTF=1;                AC_SUBST([HAVE_DECL_CBRTF])
+  HAVE_DECL_CBRTL=1;                AC_SUBST([HAVE_DECL_CBRTL])
+  HAVE_DECL_CEILF=1;                AC_SUBST([HAVE_DECL_CEILF])
+  HAVE_DECL_CEILL=1;                AC_SUBST([HAVE_DECL_CEILL])
+  HAVE_DECL_COPYSIGNF=1;            AC_SUBST([HAVE_DECL_COPYSIGNF])
+  HAVE_DECL_COSL=1;                 AC_SUBST([HAVE_DECL_COSL])
+  HAVE_DECL_EXPL=1;                 AC_SUBST([HAVE_DECL_EXPL])
+  HAVE_DECL_EXP2=1;                 AC_SUBST([HAVE_DECL_EXP2])
+  HAVE_DECL_EXP2F=1;                AC_SUBST([HAVE_DECL_EXP2F])
+  HAVE_DECL_EXP2L=1;                AC_SUBST([HAVE_DECL_EXP2L])
+  HAVE_DECL_EXPM1L=1;               AC_SUBST([HAVE_DECL_EXPM1L])
+  HAVE_DECL_FLOORF=1;               AC_SUBST([HAVE_DECL_FLOORF])
+  HAVE_DECL_FLOORL=1;               AC_SUBST([HAVE_DECL_FLOORL])
+  HAVE_DECL_FREXPL=1;               AC_SUBST([HAVE_DECL_FREXPL])
+  HAVE_DECL_LDEXPL=1;               AC_SUBST([HAVE_DECL_LDEXPL])
+  HAVE_DECL_LOGL=1;                 AC_SUBST([HAVE_DECL_LOGL])
+  HAVE_DECL_LOG10L=1;               AC_SUBST([HAVE_DECL_LOG10L])
+  HAVE_DECL_LOG2=1;                 AC_SUBST([HAVE_DECL_LOG2])
+  HAVE_DECL_LOG2F=1;                AC_SUBST([HAVE_DECL_LOG2F])
+  HAVE_DECL_LOG2L=1;                AC_SUBST([HAVE_DECL_LOG2L])
+  HAVE_DECL_LOGB=1;                 AC_SUBST([HAVE_DECL_LOGB])
+  HAVE_DECL_REMAINDER=1;            AC_SUBST([HAVE_DECL_REMAINDER])
+  HAVE_DECL_REMAINDERL=1;           AC_SUBST([HAVE_DECL_REMAINDERL])
+  HAVE_DECL_RINTF=1;                AC_SUBST([HAVE_DECL_RINTF])
+  HAVE_DECL_ROUND=1;                AC_SUBST([HAVE_DECL_ROUND])
+  HAVE_DECL_ROUNDF=1;               AC_SUBST([HAVE_DECL_ROUNDF])
+  HAVE_DECL_ROUNDL=1;               AC_SUBST([HAVE_DECL_ROUNDL])
+  HAVE_DECL_SINL=1;                 AC_SUBST([HAVE_DECL_SINL])
+  HAVE_DECL_SQRTL=1;                AC_SUBST([HAVE_DECL_SQRTL])
+  HAVE_DECL_TANL=1;                 AC_SUBST([HAVE_DECL_TANL])
+  HAVE_DECL_TRUNC=1;                AC_SUBST([HAVE_DECL_TRUNC])
+  HAVE_DECL_TRUNCF=1;               AC_SUBST([HAVE_DECL_TRUNCF])
+  HAVE_DECL_TRUNCL=1;               AC_SUBST([HAVE_DECL_TRUNCL])
+  REPLACE_ACOSF=0;                  AC_SUBST([REPLACE_ACOSF])
+  REPLACE_ASINF=0;                  AC_SUBST([REPLACE_ASINF])
+  REPLACE_ATANF=0;                  AC_SUBST([REPLACE_ATANF])
+  REPLACE_ATAN2F=0;                 AC_SUBST([REPLACE_ATAN2F])
+  REPLACE_CBRTF=0;                  AC_SUBST([REPLACE_CBRTF])
+  REPLACE_CBRTL=0;                  AC_SUBST([REPLACE_CBRTL])
+  REPLACE_CEIL=0;                   AC_SUBST([REPLACE_CEIL])
+  REPLACE_CEILF=0;                  AC_SUBST([REPLACE_CEILF])
+  REPLACE_CEILL=0;                  AC_SUBST([REPLACE_CEILL])
+  REPLACE_COSF=0;                   AC_SUBST([REPLACE_COSF])
+  REPLACE_COSHF=0;                  AC_SUBST([REPLACE_COSHF])
+  REPLACE_EXPF=0;                   AC_SUBST([REPLACE_EXPF])
+  REPLACE_EXPL=0;                   AC_SUBST([REPLACE_EXPL])
+  REPLACE_EXPM1=0;                  AC_SUBST([REPLACE_EXPM1])
+  REPLACE_EXPM1F=0;                 AC_SUBST([REPLACE_EXPM1F])
+  REPLACE_EXPM1L=0;                 AC_SUBST([REPLACE_EXPM1L])
+  REPLACE_EXP2=0;                   AC_SUBST([REPLACE_EXP2])
+  REPLACE_EXP2L=0;                  AC_SUBST([REPLACE_EXP2L])
+  REPLACE_FABSL=0;                  AC_SUBST([REPLACE_FABSL])
+  REPLACE_FLOOR=0;                  AC_SUBST([REPLACE_FLOOR])
+  REPLACE_FLOORF=0;                 AC_SUBST([REPLACE_FLOORF])
+  REPLACE_FLOORL=0;                 AC_SUBST([REPLACE_FLOORL])
+  REPLACE_FMA=0;                    AC_SUBST([REPLACE_FMA])
+  REPLACE_FMAF=0;                   AC_SUBST([REPLACE_FMAF])
+  REPLACE_FMAL=0;                   AC_SUBST([REPLACE_FMAL])
+  REPLACE_FMOD=0;                   AC_SUBST([REPLACE_FMOD])
+  REPLACE_FMODF=0;                  AC_SUBST([REPLACE_FMODF])
+  REPLACE_FMODL=0;                  AC_SUBST([REPLACE_FMODL])
+  REPLACE_FREXPF=0;                 AC_SUBST([REPLACE_FREXPF])
+  REPLACE_FREXP=0;                  AC_SUBST([REPLACE_FREXP])
+  REPLACE_FREXPL=0;                 AC_SUBST([REPLACE_FREXPL])
+  REPLACE_HUGE_VAL=0;               AC_SUBST([REPLACE_HUGE_VAL])
+  REPLACE_HYPOT=0;                  AC_SUBST([REPLACE_HYPOT])
+  REPLACE_HYPOTF=0;                 AC_SUBST([REPLACE_HYPOTF])
+  REPLACE_HYPOTL=0;                 AC_SUBST([REPLACE_HYPOTL])
+  REPLACE_ILOGB=0;                  AC_SUBST([REPLACE_ILOGB])
+  REPLACE_ILOGBF=0;                 AC_SUBST([REPLACE_ILOGBF])
+  REPLACE_ILOGBL=0;                 AC_SUBST([REPLACE_ILOGBL])
+  REPLACE_ISFINITE=0;               AC_SUBST([REPLACE_ISFINITE])
+  REPLACE_ISINF=0;                  AC_SUBST([REPLACE_ISINF])
+  REPLACE_ISNAN=0;                  AC_SUBST([REPLACE_ISNAN])
+  REPLACE_LDEXPL=0;                 AC_SUBST([REPLACE_LDEXPL])
+  REPLACE_LOG=0;                    AC_SUBST([REPLACE_LOG])
+  REPLACE_LOGF=0;                   AC_SUBST([REPLACE_LOGF])
+  REPLACE_LOGL=0;                   AC_SUBST([REPLACE_LOGL])
+  REPLACE_LOG10=0;                  AC_SUBST([REPLACE_LOG10])
+  REPLACE_LOG10F=0;                 AC_SUBST([REPLACE_LOG10F])
+  REPLACE_LOG10L=0;                 AC_SUBST([REPLACE_LOG10L])
+  REPLACE_LOG1P=0;                  AC_SUBST([REPLACE_LOG1P])
+  REPLACE_LOG1PF=0;                 AC_SUBST([REPLACE_LOG1PF])
+  REPLACE_LOG1PL=0;                 AC_SUBST([REPLACE_LOG1PL])
+  REPLACE_LOG2=0;                   AC_SUBST([REPLACE_LOG2])
+  REPLACE_LOG2F=0;                  AC_SUBST([REPLACE_LOG2F])
+  REPLACE_LOG2L=0;                  AC_SUBST([REPLACE_LOG2L])
+  REPLACE_LOGB=0;                   AC_SUBST([REPLACE_LOGB])
+  REPLACE_LOGBF=0;                  AC_SUBST([REPLACE_LOGBF])
+  REPLACE_LOGBL=0;                  AC_SUBST([REPLACE_LOGBL])
+  REPLACE_MODF=0;                   AC_SUBST([REPLACE_MODF])
+  REPLACE_MODFF=0;                  AC_SUBST([REPLACE_MODFF])
+  REPLACE_MODFL=0;                  AC_SUBST([REPLACE_MODFL])
+  REPLACE_NAN=0;                    AC_SUBST([REPLACE_NAN])
+  REPLACE_REMAINDER=0;              AC_SUBST([REPLACE_REMAINDER])
+  REPLACE_REMAINDERF=0;             AC_SUBST([REPLACE_REMAINDERF])
+  REPLACE_REMAINDERL=0;             AC_SUBST([REPLACE_REMAINDERL])
+  REPLACE_RINTL=0;                  AC_SUBST([REPLACE_RINTL])
+  REPLACE_ROUND=0;                  AC_SUBST([REPLACE_ROUND])
+  REPLACE_ROUNDF=0;                 AC_SUBST([REPLACE_ROUNDF])
+  REPLACE_ROUNDL=0;                 AC_SUBST([REPLACE_ROUNDL])
+  REPLACE_SIGNBIT=0;                AC_SUBST([REPLACE_SIGNBIT])
+  REPLACE_SIGNBIT_USING_BUILTINS=0; AC_SUBST([REPLACE_SIGNBIT_USING_BUILTINS])
+  REPLACE_SINF=0;                   AC_SUBST([REPLACE_SINF])
+  REPLACE_SINHF=0;                  AC_SUBST([REPLACE_SINHF])
+  REPLACE_SQRTF=0;                  AC_SUBST([REPLACE_SQRTF])
+  REPLACE_SQRTL=0;                  AC_SUBST([REPLACE_SQRTL])
+  REPLACE_TANF=0;                   AC_SUBST([REPLACE_TANF])
+  REPLACE_TANHF=0;                  AC_SUBST([REPLACE_TANHF])
+  REPLACE_TRUNC=0;                  AC_SUBST([REPLACE_TRUNC])
+  REPLACE_TRUNCF=0;                 AC_SUBST([REPLACE_TRUNCF])
+  REPLACE_TRUNCL=0;                 AC_SUBST([REPLACE_TRUNCL])
 ])
 
 # gl_LONG_DOUBLE_VS_DOUBLE
diff --git a/gl/m4/mbrtowc.m4 b/gl/m4/mbrtowc.m4
index 4c9f3886..bb393041 100644
--- a/gl/m4/mbrtowc.m4
+++ b/gl/m4/mbrtowc.m4
@@ -1,5 +1,5 @@
-# mbrtowc.m4 serial 25
-dnl Copyright (C) 2001-2002, 2004-2005, 2008-2013 Free Software Foundation,
+# mbrtowc.m4 serial 38  -*- coding: utf-8 -*-
+dnl Copyright (C) 2001-2002, 2004-2005, 2008-2023 Free Software Foundation,
 dnl Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -8,6 +8,8 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_MBRTOWC],
 [
   AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  AC_REQUIRE([gl_PTHREADLIB])
+  AC_CHECK_HEADERS_ONCE([threads.h])
 
   AC_REQUIRE([AC_TYPE_MBSTATE_T])
   gl_MBSTATE_T_BROKEN
@@ -16,15 +18,8 @@ AC_DEFUN([gl_FUNC_MBRTOWC],
   if test $ac_cv_func_mbrtowc = no; then
     HAVE_MBRTOWC=0
     AC_CHECK_DECLS([mbrtowc],,, [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]])
+      #include <wchar.h>
+    ]])
     if test $ac_cv_have_decl_mbrtowc = yes; then
       dnl On Minix 3.1.8, the system's <wchar.h> declares mbrtowc() although
       dnl it does not have the function. Avoid a collision with gnulib's
@@ -39,6 +34,9 @@ AC_DEFUN([gl_FUNC_MBRTOWC],
       gl_MBRTOWC_NULL_ARG2
       gl_MBRTOWC_RETVAL
       gl_MBRTOWC_NUL_RETVAL
+      gl_MBRTOWC_STORES_INCOMPLETE
+      gl_MBRTOWC_EMPTY_INPUT
+      gl_MBRTOWC_C_LOCALE
       case "$gl_cv_func_mbrtowc_null_arg1" in
         *yes) ;;
         *) AC_DEFINE([MBRTOWC_NULL_ARG1_BUG], [1],
@@ -67,8 +65,47 @@ AC_DEFUN([gl_FUNC_MBRTOWC],
            REPLACE_MBRTOWC=1
            ;;
       esac
+      case "$gl_cv_func_mbrtowc_stores_incomplete" in
+        *no) ;;
+        *) AC_DEFINE([MBRTOWC_STORES_INCOMPLETE_BUG], [1],
+             [Define if the mbrtowc function stores a wide character when reporting incomplete input.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+      case "$gl_cv_func_mbrtowc_empty_input" in
+        *yes) ;;
+        *) AC_DEFINE([MBRTOWC_EMPTY_INPUT_BUG], [1],
+             [Define if the mbrtowc function does not return (size_t) -2
+              for empty input.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+      case "$gl_cv_func_mbrtowc_C_locale_sans_EILSEQ" in
+        *yes) ;;
+        *) AC_DEFINE([MBRTOWC_IN_C_LOCALE_MAYBE_EILSEQ], [1],
+             [Define if the mbrtowc function may signal encoding errors in the C locale.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
     fi
   fi
+  if test $REPLACE_MBSTATE_T = 1; then
+    case "$host_os" in
+      mingw*) LIB_MBRTOWC= ;;
+      *)
+        gl_WEAK_SYMBOLS
+        case "$gl_cv_have_weak" in
+          *yes) LIB_MBRTOWC= ;;
+          *)    LIB_MBRTOWC="$LIBPTHREAD" ;;
+        esac
+        ;;
+    esac
+  else
+    LIB_MBRTOWC=
+  fi
+  dnl LIB_MBRTOWC is expected to be '-pthread' or '-lpthread' on AIX
+  dnl with gcc or xlc, and empty otherwise.
+  AC_SUBST([LIB_MBRTOWC])
 ])
 
 dnl Test whether mbsinit() and mbrtowc() need to be overridden in a way that
@@ -80,11 +117,19 @@ dnl avoid inconsistencies.
 AC_DEFUN([gl_MBSTATE_T_BROKEN],
 [
   AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
 
   AC_REQUIRE([AC_TYPE_MBSTATE_T])
   AC_CHECK_FUNCS_ONCE([mbsinit])
   AC_CHECK_FUNCS_ONCE([mbrtowc])
-  if test $ac_cv_func_mbsinit = yes && test $ac_cv_func_mbrtowc = yes; then
+  dnl On native Windows, we know exactly how mbsinit() behaves and don't need
+  dnl to override it, even if - like on MSVC - mbsinit() is only defined as
+  dnl an inline function, not as a global function.
+  if case "$host_os" in
+       mingw*) true ;;
+       *) test $ac_cv_func_mbsinit = yes ;;
+     esac \
+    && test $ac_cv_func_mbrtowc = yes; then
     gl_MBRTOWC_INCOMPLETE_STATE
     gl_MBRTOWC_SANITYCHECK
     REPLACE_MBSTATE_T=0
@@ -109,6 +154,7 @@ AC_DEFUN([gl_MBRTOWC_INCOMPLETE_STATE],
 [
   AC_REQUIRE([AC_PROG_CC])
   AC_REQUIRE([gt_LOCALE_JA])
+  AC_REQUIRE([gt_LOCALE_FR_UTF8])
   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
   AC_CACHE_CHECK([whether mbrtowc handles incomplete characters],
     [gl_cv_func_mbrtowc_incomplete_state],
@@ -128,13 +174,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -147,13 +186,39 @@ int main ()
       memset (&state, '\0', sizeof (mbstate_t));
       if (mbrtowc (&wc, input + 1, 1, &state) == (size_t)(-2))
         if (mbsinit (&state))
-          return 1;
+          return 2;
+    }
+  return 0;
+}]])],
+          [gl_cv_func_mbrtowc_incomplete_state=yes],
+          [gl_cv_func_mbrtowc_incomplete_state=no],
+          [:])
+      else
+        if test $LOCALE_FR_UTF8 != none; then
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      const char input[] = "B\303\274\303\237er"; /* "Büßer" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 1, 1, &state) == (size_t)(-2))
+        if (mbsinit (&state))
+          return 2;
     }
   return 0;
 }]])],
           [gl_cv_func_mbrtowc_incomplete_state=yes],
           [gl_cv_func_mbrtowc_incomplete_state=no],
           [:])
+        fi
       fi
     ])
 ])
@@ -185,13 +250,6 @@ changequote([,])dnl
 #include <locale.h>
 #include <stdlib.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -207,7 +265,7 @@ int main ()
       memset (&state, '\0', sizeof (mbstate_t));
       if (mbrtowc (&wc, input + 3, 6, &state) != 4
           && mbtowc (&wc, input + 3, 6) == 4)
-        return 1;
+        return 2;
     }
   return 0;
 }]])],
@@ -245,13 +303,6 @@ changequote([,])dnl
 #include <locale.h>
 #include <stdlib.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -314,13 +365,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -335,7 +379,7 @@ int main ()
       mbrtowc (&wc, NULL, 5, &state);
       /* Check that wc was not modified.  */
       if (wc != (wchar_t) 0xBADFACE)
-        return 1;
+        return 2;
     }
   return 0;
 }]])],
@@ -376,13 +420,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -504,13 +541,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -522,7 +552,7 @@ int main ()
 
       memset (&state, '\0', sizeof (mbstate_t));
       if (mbrtowc (&wc, "", 1, &state) != 0)
-        return 1;
+        return 2;
     }
   return 0;
 }]])],
@@ -533,11 +563,206 @@ int main ()
     ])
 ])
 
-# Prerequisites of lib/mbrtowc.c.
+dnl Test whether mbrtowc stores a wide character when reporting incomplete
+dnl input.
+
+AC_DEFUN([gl_MBRTOWC_STORES_INCOMPLETE],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc stores incomplete characters],
+    [gl_cv_func_mbrtowc_stores_incomplete],
+    [
+     dnl Initial guess, used when cross-compiling or when no suitable locale
+     dnl is present.
+changequote(,)dnl
+     case "$host_os" in
+               # Guess yes on native Windows.
+       mingw*) gl_cv_func_mbrtowc_stores_incomplete="guessing yes" ;;
+       *)      gl_cv_func_mbrtowc_stores_incomplete="guessing no" ;;
+     esac
+changequote([,])dnl
+     case "$host_os" in
+       mingw*)
+         AC_RUN_IFELSE(
+           [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  int result = 0;
+  if (setlocale (LC_ALL, "French_France.65001") != NULL)
+    {
+      wchar_t wc = (wchar_t) 0xBADFACE;
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, "\303", 1, &state) == (size_t)(-2)
+          && wc != (wchar_t) 0xBADFACE)
+        result |= 1;
+    }
+  if (setlocale (LC_ALL, "Japanese_Japan.932") != NULL)
+    {
+      wchar_t wc = (wchar_t) 0xBADFACE;
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, "\226", 1, &state) == (size_t)(-2)
+          && wc != (wchar_t) 0xBADFACE)
+        result |= 2;
+    }
+  if (setlocale (LC_ALL, "Chinese_Taiwan.950") != NULL)
+    {
+      wchar_t wc = (wchar_t) 0xBADFACE;
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, "\245", 1, &state) == (size_t)(-2)
+          && wc != (wchar_t) 0xBADFACE)
+        result |= 4;
+    }
+  if (setlocale (LC_ALL, "Chinese_China.936") != NULL)
+    {
+      wchar_t wc = (wchar_t) 0xBADFACE;
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, "\261", 1, &state) == (size_t)(-2)
+          && wc != (wchar_t) 0xBADFACE)
+        result |= 8;
+    }
+  return result;
+}]])],
+           [gl_cv_func_mbrtowc_stores_incomplete=no],
+           [gl_cv_func_mbrtowc_stores_incomplete=yes],
+           [:])
+         ;;
+       *)
+         AC_REQUIRE([gt_LOCALE_FR_UTF8])
+         if test $LOCALE_FR_UTF8 != none; then
+           AC_RUN_IFELSE(
+             [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      wchar_t wc = (wchar_t) 0xBADFACE;
+      mbstate_t state;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, "\303", 1, &state) == (size_t)(-2)
+          && wc != (wchar_t) 0xBADFACE)
+        return 1;
+    }
+  return 0;
+}]])],
+             [gl_cv_func_mbrtowc_stores_incomplete=no],
+             [gl_cv_func_mbrtowc_stores_incomplete=yes],
+             [:])
+         fi
+         ;;
+     esac
+    ])
+])
+
+dnl Test whether mbrtowc returns the correct value on empty input.
+
+AC_DEFUN([gl_MBRTOWC_EMPTY_INPUT],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc works on empty input],
+    [gl_cv_func_mbrtowc_empty_input],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                              # Guess no on AIX and glibc systems.
+        aix* | *-gnu* | gnu*) gl_cv_func_mbrtowc_empty_input="guessing no" ;;
+                              # Guess yes on native Windows.
+        mingw*)               gl_cv_func_mbrtowc_empty_input="guessing yes" ;;
+        *)                    gl_cv_func_mbrtowc_empty_input="guessing yes" ;;
+      esac
+changequote([,])dnl
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+           #include <wchar.h>
+           static wchar_t wc;
+           static mbstate_t mbs;
+           int
+           main (void)
+           {
+             return mbrtowc (&wc, "", 0, &mbs) != (size_t) -2;
+           }]])],
+        [gl_cv_func_mbrtowc_empty_input=yes],
+        [gl_cv_func_mbrtowc_empty_input=no],
+        [:])
+    ])
+])
+
+dnl Test whether mbrtowc reports encoding errors in the C locale.
+dnl Although POSIX was never intended to allow this, the GNU C Library
+dnl and other implementations do it.  See:
+dnl https://sourceware.org/bugzilla/show_bug.cgi?id=19932
+
+AC_DEFUN([gl_MBRTOWC_C_LOCALE],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether the C locale is free of encoding errors],
+    [gl_cv_func_mbrtowc_C_locale_sans_EILSEQ],
+    [
+     dnl Initial guess, used when cross-compiling or when no suitable locale
+     dnl is present.
+     gl_cv_func_mbrtowc_C_locale_sans_EILSEQ="$gl_cross_guess_normal"
+
+     AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <limits.h>
+            #include <locale.h>
+            #include <wchar.h>
+          ]], [[
+            int i;
+            char *locale = setlocale (LC_ALL, "C");
+            if (! locale)
+              return 2;
+            for (i = CHAR_MIN; i <= CHAR_MAX; i++)
+              {
+                char c = i;
+                wchar_t wc;
+                mbstate_t mbs = { 0, };
+                size_t ss = mbrtowc (&wc, &c, 1, &mbs);
+                if (1 < ss)
+                  return 3;
+              }
+            return 0;
+          ]])],
+      [gl_cv_func_mbrtowc_C_locale_sans_EILSEQ=yes],
+      [gl_cv_func_mbrtowc_C_locale_sans_EILSEQ=no],
+      [case "$host_os" in
+                 # Guess yes on native Windows.
+         mingw*) gl_cv_func_mbrtowc_C_locale_sans_EILSEQ="guessing yes" ;;
+       esac
+      ])
+    ])
+])
+
+# Prerequisites of lib/mbrtowc.c and lib/lc-charset-dispatch.c.
 AC_DEFUN([gl_PREREQ_MBRTOWC], [
+  AC_REQUIRE([AC_C_INLINE])
   :
 ])
 
+# Prerequisites of lib/mbtowc-lock.c.
+AC_DEFUN([gl_PREREQ_MBTOWC_LOCK],
+[
+  gl_VISIBILITY
+])
+
 
 dnl From Paul Eggert
 
@@ -547,24 +772,17 @@ AC_DEFUN([AC_FUNC_MBRTOWC],
 [
   dnl Same as AC_FUNC_MBRTOWC in autoconf-2.60.
   AC_CACHE_CHECK([whether mbrtowc and mbstate_t are properly declared],
-    gl_cv_func_mbrtowc,
+    [gl_cv_func_mbrtowc],
     [AC_LINK_IFELSE(
        [AC_LANG_PROGRAM(
-            [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
-                 included before <wchar.h>.
-                 BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
-                 must be included before <wchar.h>.  */
-              #include <stddef.h>
-              #include <stdio.h>
-              #include <time.h>
-              #include <wchar.h>]],
+            [[#include <wchar.h>]],
             [[wchar_t wc;
               char const s[] = "";
               size_t n = 1;
               mbstate_t state;
               return ! (sizeof state && (mbrtowc) (&wc, s, n, &state));]])],
-       gl_cv_func_mbrtowc=yes,
-       gl_cv_func_mbrtowc=no)])
+       [gl_cv_func_mbrtowc=yes],
+       [gl_cv_func_mbrtowc=no])])
   if test $gl_cv_func_mbrtowc = yes; then
     AC_DEFINE([HAVE_MBRTOWC], [1],
       [Define to 1 if mbrtowc and mbstate_t are properly declared.])
diff --git a/gl/m4/mbsinit.m4 b/gl/m4/mbsinit.m4
index 2e6d0921..c388a8b9 100644
--- a/gl/m4/mbsinit.m4
+++ b/gl/m4/mbsinit.m4
@@ -1,5 +1,5 @@
-# mbsinit.m4 serial 8
-dnl Copyright (C) 2008, 2010-2013 Free Software Foundation, Inc.
+# mbsinit.m4 serial 9
+dnl Copyright (C) 2008, 2010-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -16,15 +16,8 @@ AC_DEFUN([gl_FUNC_MBSINIT],
   if test $ac_cv_func_mbsinit = no; then
     HAVE_MBSINIT=0
     AC_CHECK_DECLS([mbsinit],,, [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]])
+      #include <wchar.h>
+    ]])
     if test $ac_cv_have_decl_mbsinit = yes; then
       dnl On Minix 3.1.8, the system's <wchar.h> declares mbsinit() although
       dnl it does not have the function. Avoid a collision with gnulib's
diff --git a/gl/m4/mbstate_t.m4 b/gl/m4/mbstate_t.m4
index ed001179..dcd66b96 100644
--- a/gl/m4/mbstate_t.m4
+++ b/gl/m4/mbstate_t.m4
@@ -1,5 +1,5 @@
-# mbstate_t.m4 serial 13
-dnl Copyright (C) 2000-2002, 2008-2013 Free Software Foundation, Inc.
+# mbstate_t.m4 serial 14
+dnl Copyright (C) 2000-2002, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -20,14 +20,7 @@ AC_DEFUN([AC_TYPE_MBSTATE_T],
      [AC_COMPILE_IFELSE(
         [AC_LANG_PROGRAM(
            [AC_INCLUDES_DEFAULT[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>]],
+             #include <wchar.h>]],
            [[mbstate_t x; return sizeof x;]])],
         [ac_cv_type_mbstate_t=yes],
         [ac_cv_type_mbstate_t=no])])
diff --git a/gl/m4/mbtowc.m4 b/gl/m4/mbtowc.m4
index e4794619..7823be0e 100644
--- a/gl/m4/mbtowc.m4
+++ b/gl/m4/mbtowc.m4
@@ -1,5 +1,5 @@
-# mbtowc.m4 serial 2
-dnl Copyright (C) 2011-2013 Free Software Foundation, Inc.
+# mbtowc.m4 serial 3
+dnl Copyright (C) 2011-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -8,8 +8,13 @@ AC_DEFUN([gl_FUNC_MBTOWC],
 [
   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
 
-  if false; then
-    REPLACE_MBTOWC=1
+  AC_CHECK_FUNCS([mbtowc])
+  if test $ac_cv_func_mbtowc = no; then
+    HAVE_MBTOWC=0
+  else
+    if false; then
+      REPLACE_MBTOWC=1
+    fi
   fi
 ])
 
diff --git a/gl/m4/memchr.m4 b/gl/m4/memchr.m4
index 2d8abe75..4f1aed01 100644
--- a/gl/m4/memchr.m4
+++ b/gl/m4/memchr.m4
@@ -1,35 +1,30 @@
-# memchr.m4 serial 12
-dnl Copyright (C) 2002-2004, 2009-2013 Free Software Foundation, Inc.
+# memchr.m4 serial 18
+dnl Copyright (C) 2002-2004, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN_ONCE([gl_FUNC_MEMCHR],
 [
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
   dnl Check for prerequisites for memory fence checks.
   gl_FUNC_MMAP_ANON
   AC_CHECK_HEADERS_ONCE([sys/mman.h])
   AC_CHECK_FUNCS_ONCE([mprotect])
 
-  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
-  m4_ifdef([gl_FUNC_MEMCHR_OBSOLETE], [
-    dnl These days, we assume memchr is present.  But if support for old
-    dnl platforms is desired:
-    AC_CHECK_FUNCS_ONCE([memchr])
-    if test $ac_cv_func_memchr = no; then
-      HAVE_MEMCHR=0
-    fi
-  ])
-  if test $HAVE_MEMCHR = 1; then
-    # Detect platform-specific bugs in some versions of glibc:
-    # memchr should not dereference anything with length 0
-    #   http://bugzilla.redhat.com/499689
-    # memchr should not dereference overestimated length after a match
-    #   http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521737
-    #   http://sourceware.org/bugzilla/show_bug.cgi?id=10162
-    # Assume that memchr works on platforms that lack mprotect.
-    AC_CACHE_CHECK([whether memchr works], [gl_cv_func_memchr_works],
-      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+  AC_REQUIRE([gl_STRING_H_DEFAULTS])
+  # Detect platform-specific bugs in some versions of glibc:
+  # memchr should not dereference anything with length 0
+  #   https://bugzilla.redhat.com/show_bug.cgi?id=499689
+  # memchr should not dereference overestimated length after a match
+  #   https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521737
+  #   https://sourceware.org/bugzilla/show_bug.cgi?id=10162
+  # memchr should cast the second argument to 'unsigned char'.
+  #   This bug exists in Android 4.3.
+  # Assume that memchr works on platforms that lack mprotect.
+  AC_CACHE_CHECK([whether memchr works], [gl_cv_func_memchr_works],
+    [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
 #include <string.h>
 #if HAVE_SYS_MMAN_H
 # include <fcntl.h>
@@ -64,6 +59,7 @@ AC_DEFUN_ONCE([gl_FUNC_MEMCHR],
 #endif
   if (fence)
     {
+      /* Test against bugs on glibc systems.  */
       if (memchr (fence, 0, 0))
         result |= 1;
       strcpy (fence - 9, "12345678");
@@ -71,15 +67,37 @@ AC_DEFUN_ONCE([gl_FUNC_MEMCHR],
         result |= 2;
       if (memchr (fence - 1, 0, 3) != fence - 1)
         result |= 4;
+      /* Test against bug on AIX 7.2.  */
+      if (memchr (fence - 4, '6', 16) != fence - 4)
+        result |= 8;
     }
+  /* Test against bug on Android 4.3.  */
+  {
+    char input[3];
+    input[0] = 'a';
+    input[1] = 'b';
+    input[2] = 'c';
+    if (memchr (input, 0x789abc00 | 'b', 3) != input + 1)
+      result |= 16;
+  }
   return result;
-]])], [gl_cv_func_memchr_works=yes], [gl_cv_func_memchr_works=no],
-      [dnl Be pessimistic for now.
-       gl_cv_func_memchr_works="guessing no"])])
-    if test "$gl_cv_func_memchr_works" != yes; then
-      REPLACE_MEMCHR=1
-    fi
-  fi
+]])],
+       [gl_cv_func_memchr_works=yes],
+       [gl_cv_func_memchr_works=no],
+       [case "$host_os" in
+                           # Guess no on Android.
+          linux*-android*) gl_cv_func_memchr_works="guessing no" ;;
+                           # Guess yes on native Windows.
+          mingw*)          gl_cv_func_memchr_works="guessing yes" ;;
+                           # If we don't know, obey --enable-cross-guesses.
+          *)               gl_cv_func_memchr_works="$gl_cross_guess_normal" ;;
+        esac
+       ])
+    ])
+  case "$gl_cv_func_memchr_works" in
+    *yes) ;;
+    *) REPLACE_MEMCHR=1 ;;
+  esac
 ])
 
 # Prerequisites of lib/memchr.c.
diff --git a/gl/m4/minmax.m4 b/gl/m4/minmax.m4
new file mode 100644
index 00000000..fd09846f
--- /dev/null
+++ b/gl/m4/minmax.m4
@@ -0,0 +1,44 @@
+# minmax.m4 serial 4
+dnl Copyright (C) 2005, 2009-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_PREREQ([2.53])
+
+AC_DEFUN([gl_MINMAX],
+[
+  AC_REQUIRE([gl_PREREQ_MINMAX])
+])
+
+# Prerequisites of lib/minmax.h.
+AC_DEFUN([gl_PREREQ_MINMAX],
+[
+  gl_MINMAX_IN_HEADER([limits.h])
+  gl_MINMAX_IN_HEADER([sys/param.h])
+])
+
+dnl gl_MINMAX_IN_HEADER(HEADER)
+dnl The parameter has to be a literal header name; it cannot be macro,
+dnl nor a shell variable. (Because autoheader collects only AC_DEFINE
+dnl invocations with a literal macro name.)
+AC_DEFUN([gl_MINMAX_IN_HEADER],
+[
+  m4_pushdef([header], AS_TR_SH([$1]))
+  m4_pushdef([HEADER], AS_TR_CPP([$1]))
+  AC_CACHE_CHECK([whether <$1> defines MIN and MAX],
+    [gl_cv_minmax_in_]header,
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <$1>
+            int x = MIN (42, 17);]],
+          [[]])],
+       [gl_cv_minmax_in_]header[=yes],
+       [gl_cv_minmax_in_]header[=no])])
+  if test $gl_cv_minmax_in_[]header = yes; then
+    AC_DEFINE([HAVE_MINMAX_IN_]HEADER, 1,
+      [Define to 1 if <$1> defines the MIN and MAX macros.])
+  fi
+  m4_popdef([HEADER])
+  m4_popdef([header])
+])
diff --git a/gl/m4/mktime.m4 b/gl/m4/mktime.m4
index faefb770..e9d31f35 100644
--- a/gl/m4/mktime.m4
+++ b/gl/m4/mktime.m4
@@ -1,5 +1,5 @@
-# serial 25
-dnl Copyright (C) 2002-2003, 2005-2007, 2009-2013 Free Software Foundation,
+# serial 37
+dnl Copyright (C) 2002-2003, 2005-2007, 2009-2023 Free Software Foundation,
 dnl Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,24 +7,40 @@ dnl with or without modifications, as long as this notice is preserved.
 
 dnl From Jim Meyering.
 
-AC_DEFUN([gl_FUNC_MKTIME],
+AC_DEFUN([gl_TIME_T_IS_SIGNED],
+[
+  AC_CACHE_CHECK([whether time_t is signed],
+    [gl_cv_time_t_is_signed],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM([[#include <time.h>
+                          char time_t_signed[(time_t) -1 < 0 ? 1 : -1];]])],
+       [gl_cv_time_t_is_signed=yes],
+       [gl_cv_time_t_is_signed=no])])
+  if test $gl_cv_time_t_is_signed = yes; then
+    AC_DEFINE([TIME_T_IS_SIGNED], [1], [Define to 1 if time_t is signed.])
+  fi
+])
+
+dnl Test whether mktime works. Set gl_cv_func_working_mktime.
+AC_DEFUN([gl_FUNC_MKTIME_WORKS],
 [
-  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
+  AC_REQUIRE([gl_TIME_T_IS_SIGNED])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
 
   dnl We don't use AC_FUNC_MKTIME any more, because it is no longer maintained
   dnl in Autoconf and because it invokes AC_LIBOBJ.
   AC_CHECK_HEADERS_ONCE([unistd.h])
   AC_CHECK_DECLS_ONCE([alarm])
   AC_REQUIRE([gl_MULTIARCH])
-  if test $APPLE_UNIVERSAL_BUILD = 1; then
-    # A universal build on Apple Mac OS X platforms.
-    # The test result would be 'yes' in 32-bit mode and 'no' in 64-bit mode.
-    # But we need a configuration result that is valid in both modes.
-    gl_cv_func_working_mktime=no
-  fi
   AC_CACHE_CHECK([for working mktime], [gl_cv_func_working_mktime],
-    [AC_RUN_IFELSE(
-       [AC_LANG_SOURCE(
+    [if test $APPLE_UNIVERSAL_BUILD = 1; then
+       # A universal build on Apple Mac OS X platforms.
+       # The test result would be 'yes' in 32-bit mode and 'no' in 64-bit mode.
+       # But we need a configuration result that is valid in both modes.
+       gl_cv_func_working_mktime="guessing no"
+     else
+       AC_RUN_IFELSE(
+         [AC_LANG_SOURCE(
 [[/* Test program from Paul Eggert and Tony Leneis.  */
 #include <limits.h>
 #include <stdlib.h>
@@ -38,8 +54,11 @@ AC_DEFUN([gl_FUNC_MKTIME],
 # include <signal.h>
 #endif
 
-/* Work around redefinition to rpl_putenv by other config tests.  */
-#undef putenv
+]GL_MDA_DEFINES[
+
+#ifndef TIME_T_IS_SIGNED
+# define TIME_T_IS_SIGNED 0
+#endif
 
 static time_t time_t_max;
 static time_t time_t_min;
@@ -63,7 +82,8 @@ spring_forward_gap ()
      instead of "TZ=America/Vancouver" in order to detect the bug even
      on systems that don't support the Olson extension, or don't have the
      full zoneinfo tables installed.  */
-  putenv ("TZ=PST8PDT,M4.1.0,M10.5.0");
+  if (putenv ("TZ=PST8PDT,M4.1.0,M10.5.0") != 0)
+    return -1;
 
   tm.tm_year = 98;
   tm.tm_mon = 3;
@@ -151,7 +171,8 @@ year_2050_test ()
      instead of "TZ=America/Vancouver" in order to detect the bug even
      on systems that don't support the Olson extension, or don't have the
      full zoneinfo tables installed.  */
-  putenv ("TZ=PST8PDT,M4.1.0,M10.5.0");
+  if (putenv ("TZ=PST8PDT,M4.1.0,M10.5.0") != 0)
+    return -1;
 
   t = mktime (&tm);
 
@@ -162,6 +183,25 @@ year_2050_test ()
           || (0 < t && answer - 120 <= t && t <= answer + 120));
 }
 
+static int
+indiana_test ()
+{
+  if (putenv ("TZ=America/Indiana/Indianapolis") != 0)
+    return -1;
+  struct tm tm;
+  tm.tm_year = 1986 - 1900; tm.tm_mon = 4 - 1; tm.tm_mday = 28;
+  tm.tm_hour = 16; tm.tm_min = 24; tm.tm_sec = 50; tm.tm_isdst = 0;
+  time_t std = mktime (&tm);
+  if (! (std == 515107490 || std == 515107503))
+    return 1;
+
+  /* This platform supports TZDB, either without or with leap seconds.
+     Return true if GNU Bug#48085 is absent.  */
+  tm.tm_isdst = 1;
+  time_t dst = mktime (&tm);
+  return std - dst == 60 * 60;
+}
+
 int
 main ()
 {
@@ -169,7 +209,6 @@ main ()
   time_t t, delta;
   int i, j;
   int time_t_signed_magnitude = (time_t) ~ (time_t) 0 < (time_t) -1;
-  int time_t_signed = ! ((time_t) 0 < (time_t) -1);
 
 #if HAVE_DECL_ALARM
   /* This test makes some buggy mktime implementations loop.
@@ -179,11 +218,11 @@ main ()
   alarm (60);
 #endif
 
-  time_t_max = (! time_t_signed
+  time_t_max = (! TIME_T_IS_SIGNED
                 ? (time_t) -1
                 : ((((time_t) 1 << (sizeof (time_t) * CHAR_BIT - 2)) - 1)
                    * 2 + 1));
-  time_t_min = (! time_t_signed
+  time_t_min = (! TIME_T_IS_SIGNED
                 ? (time_t) 0
                 : time_t_signed_magnitude
                 ? ~ (time_t) 0
@@ -218,35 +257,62 @@ main ()
     result |= 16;
   if (! spring_forward_gap ())
     result |= 32;
-  if (! year_2050_test ())
+  if (! year_2050_test () || ! indiana_test ())
     result |= 64;
   return result;
 }]])],
-       [gl_cv_func_working_mktime=yes],
-       [gl_cv_func_working_mktime=no],
-       [gl_cv_func_working_mktime=no])
+         [gl_cv_func_working_mktime=yes],
+         [gl_cv_func_working_mktime=no],
+         [case "$host_os" in
+                    # Guess no on native Windows.
+            mingw*) gl_cv_func_working_mktime="guessing no" ;;
+            *)      gl_cv_func_working_mktime="$gl_cross_guess_normal" ;;
+          esac
+         ])
+     fi
     ])
+])
+
+dnl Main macro of module 'mktime'.
+AC_DEFUN([gl_FUNC_MKTIME],
+[
+  AC_REQUIRE([gl_TIME_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_FUNC_MKTIME_WORKS])
 
-  if test $gl_cv_func_working_mktime = no; then
+  REPLACE_MKTIME=0
+  if test "$gl_cv_func_working_mktime" != yes; then
     REPLACE_MKTIME=1
-  else
-    REPLACE_MKTIME=0
+    AC_DEFINE([NEED_MKTIME_WORKING], [1],
+      [Define if the compilation of mktime.c should define 'mktime'
+       with the algorithmic workarounds.])
   fi
+  case "$host_os" in
+    mingw*)
+      REPLACE_MKTIME=1
+      AC_DEFINE([NEED_MKTIME_WINDOWS], [1],
+        [Define if the compilation of mktime.c should define 'mktime'
+         with the native Windows TZ workaround.])
+      ;;
+  esac
 ])
 
+dnl Main macro of module 'mktime-internal'.
 AC_DEFUN([gl_FUNC_MKTIME_INTERNAL], [
-  AC_REQUIRE([gl_FUNC_MKTIME])
-  if test $REPLACE_MKTIME = 0; then
-    dnl BeOS has __mktime_internal in libc, but other platforms don't.
-    AC_CHECK_FUNC([__mktime_internal],
-      [AC_DEFINE([mktime_internal], [__mktime_internal],
-         [Define to the real name of the mktime_internal function.])
-      ],
-      [dnl mktime works but it doesn't export __mktime_internal,
-       dnl so we need to substitute our own mktime implementation.
-       REPLACE_MKTIME=1
-      ])
-  fi
+  AC_REQUIRE([gl_FUNC_MKTIME_WORKS])
+
+  WANT_MKTIME_INTERNAL=0
+  dnl BeOS has __mktime_internal in libc, but other platforms don't.
+  AC_CHECK_FUNC([__mktime_internal],
+    [AC_DEFINE([mktime_internal], [__mktime_internal],
+       [Define to the real name of the mktime_internal function.])
+    ],
+    [dnl mktime works but it doesn't export __mktime_internal,
+     dnl so we need to substitute our own mktime implementation.
+     WANT_MKTIME_INTERNAL=1
+     AC_DEFINE([NEED_MKTIME_INTERNAL], [1],
+       [Define if the compilation of mktime.c should define 'mktime_internal'.])
+    ])
 ])
 
 # Prerequisites of lib/mktime.c.
diff --git a/gl/m4/mmap-anon.m4 b/gl/m4/mmap-anon.m4
index 9b60ddfa..d07d26e4 100644
--- a/gl/m4/mmap-anon.m4
+++ b/gl/m4/mmap-anon.m4
@@ -1,5 +1,5 @@
-# mmap-anon.m4 serial 10
-dnl Copyright (C) 2005, 2007, 2009-2013 Free Software Foundation, Inc.
+# mmap-anon.m4 serial 12
+dnl Copyright (C) 2005, 2007, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -9,11 +9,11 @@ dnl with or without modifications, as long as this notice is preserved.
 # - On Linux, AIX, OSF/1, Solaris, Cygwin, Interix, Haiku, both MAP_ANONYMOUS
 #   and MAP_ANON exist and have the same value.
 # - On HP-UX, only MAP_ANONYMOUS exists.
-# - On Mac OS X, FreeBSD, NetBSD, OpenBSD, only MAP_ANON exists.
+# - On Mac OS X, FreeBSD, NetBSD, OpenBSD, Minix, only MAP_ANON exists.
 # - On IRIX, neither exists, and a file descriptor opened to /dev/zero must be
 #   used.
 
-AC_DEFUN([gl_FUNC_MMAP_ANON],
+AC_DEFUN_ONCE([gl_FUNC_MMAP_ANON],
 [
   dnl Persuade glibc <sys/mman.h> to define MAP_ANONYMOUS.
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
diff --git a/gl/m4/mode_t.m4 b/gl/m4/mode_t.m4
new file mode 100644
index 00000000..82197c02
--- /dev/null
+++ b/gl/m4/mode_t.m4
@@ -0,0 +1,26 @@
+# mode_t.m4 serial 2
+dnl Copyright (C) 2009-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# For using mode_t, it's sufficient to use AC_TYPE_MODE_T and
+# include <sys/types.h>.
+
+# Define PROMOTED_MODE_T to the type that is the result of "default argument
+# promotion" (ISO C 6.5.2.2.(6)) of the type mode_t.
+AC_DEFUN([gl_PROMOTED_TYPE_MODE_T],
+[
+  AC_REQUIRE([AC_TYPE_MODE_T])
+  AC_CACHE_CHECK([for promoted mode_t type], [gl_cv_promoted_mode_t], [
+    dnl Assume mode_t promotes to 'int' if and only if it is smaller than 'int',
+    dnl and to itself otherwise. This assumption is not guaranteed by the ISO C
+    dnl standard, but we don't know of any real-world counterexamples.
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>]],
+      [[typedef int array[2 * (sizeof (mode_t) < sizeof (int)) - 1];]])],
+      [gl_cv_promoted_mode_t='int'],
+      [gl_cv_promoted_mode_t='mode_t'])
+  ])
+  AC_DEFINE_UNQUOTED([PROMOTED_MODE_T], [$gl_cv_promoted_mode_t],
+    [Define to the type that is the result of default argument promotions of type mode_t.])
+])
diff --git a/gl/m4/mountlist.m4 b/gl/m4/mountlist.m4
index cd137c91..a9b4edb9 100644
--- a/gl/m4/mountlist.m4
+++ b/gl/m4/mountlist.m4
@@ -1,19 +1,338 @@
-# serial 11
-dnl Copyright (C) 2002-2006, 2009-2013 Free Software Foundation, Inc.
+# serial 15
+dnl Copyright (C) 2002-2006, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
+dnl From Jim Meyering.
+
+AC_PREREQ([2.60])
+
 AC_DEFUN([gl_MOUNTLIST],
 [
-  gl_LIST_MOUNTED_FILE_SYSTEMS([gl_cv_list_mounted_fs=yes],
-                               [gl_cv_list_mounted_fs=no])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CHECK_FUNCS([listmntent])
+  AC_CHECK_HEADERS_ONCE([sys/param.h sys/statvfs.h])
+
+  # We must include grp.h before ucred.h on OSF V4.0, since ucred.h uses
+  # NGROUPS (as the array dimension for a struct member) without a definition.
+  AC_CHECK_HEADERS([sys/ucred.h], [], [], [#include <grp.h>])
+
+  AC_CHECK_HEADERS([sys/mount.h], [], [],
+    [AC_INCLUDES_DEFAULT
+     [#if HAVE_SYS_PARAM_H
+       #include <sys/param.h>
+      #endif
+    ]])
+
+  AC_CHECK_HEADERS([mntent.h sys/fs_types.h])
+  getfsstat_includes="\
+$ac_includes_default
+#if HAVE_SYS_PARAM_H
+# include <sys/param.h> /* needed by powerpc-apple-darwin1.3.7 */
+#endif
+#if HAVE_SYS_UCRED_H
+# include <grp.h> /* needed for definition of NGROUPS */
+# include <sys/ucred.h> /* needed by powerpc-apple-darwin1.3.7 */
+#endif
+#if HAVE_SYS_MOUNT_H
+# include <sys/mount.h>
+#endif
+#if HAVE_SYS_FS_TYPES_H
+# include <sys/fs_types.h> /* needed by powerpc-apple-darwin1.3.7 */
+#endif
+"
+  AC_CHECK_MEMBERS([struct fsstat.f_fstypename],,,[$getfsstat_includes])
+
+  # Determine how to get the list of mounted file systems.
+  ac_list_mounted_fs=
+
+  # If the getmntent function is available but not in the standard library,
+  # make sure LIBS contains the appropriate -l option.
+  AC_FUNC_GETMNTENT
+
+  if test -z "$ac_list_mounted_fs"; then
+    # AIX.
+    AC_CACHE_CHECK([for mntctl function and struct vmount],
+      [fu_cv_sys_mounted_vmount],
+      [AC_PREPROC_IFELSE([AC_LANG_SOURCE([[#include <fshelp.h>]])],
+         [fu_cv_sys_mounted_vmount=yes],
+         [fu_cv_sys_mounted_vmount=no])])
+    if test $fu_cv_sys_mounted_vmount = yes; then
+      ac_list_mounted_fs=found
+      AC_DEFINE([MOUNTED_VMOUNT], [1],
+        [Define if there is a function named mntctl that can be used to read
+         the list of mounted file systems, and there is a system header file
+         that declares 'struct vmount'.  (AIX)])
+    fi
+  fi
+
+  if test $ac_cv_func_getmntent = yes; then
+
+    # This system has the getmntent function.
+    # Determine whether it's the one-argument variant or the two-argument one.
+
+    if test -z "$ac_list_mounted_fs"; then
+      # glibc, HP-UX, IRIX, Cygwin, Android, also (obsolete) 4.3BSD, SunOS.
+      AC_CACHE_CHECK([for one-argument getmntent function],
+        [fu_cv_sys_mounted_getmntent1],
+        [AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM([[
+/* SunOS 4.1.x /usr/include/mntent.h needs this for FILE */
+#include <stdio.h>
+
+#include <mntent.h>
+#if defined __ANDROID__        /* Android */
+# undef MOUNTED
+# define MOUNTED "/proc/mounts"
+#elif !defined MOUNTED
+# if defined _PATH_MOUNTED     /* GNU libc  */
+#  define MOUNTED _PATH_MOUNTED
+# endif
+# if defined MNT_MNTTAB        /* HP-UX.  */
+#  define MOUNTED MNT_MNTTAB
+# endif
+#endif
+]],
+              [[struct mntent *mnt = 0; char *table = MOUNTED;
+                if (sizeof mnt && sizeof table) return 0;
+              ]])],
+           [fu_cv_sys_mounted_getmntent1=yes],
+           [fu_cv_sys_mounted_getmntent1=no])
+        ])
+      if test $fu_cv_sys_mounted_getmntent1 = yes; then
+        ac_list_mounted_fs=found
+        AC_DEFINE([MOUNTED_GETMNTENT1], [1],
+          [Define if there is a function named getmntent for reading the list
+           of mounted file systems, and that function takes a single argument.
+           (4.3BSD, SunOS, HP-UX, Irix)])
+        AC_CHECK_FUNCS([setmntent endmntent hasmntopt])
+      fi
+    fi
+
+    if test -z "$ac_list_mounted_fs"; then
+      # Solaris >= 8.
+      AC_CACHE_CHECK([for getextmntent function],
+        [fu_cv_sys_mounted_getextmntent],
+        [AC_EGREP_HEADER([getextmntent], [sys/mnttab.h],
+           [fu_cv_sys_mounted_getextmntent=yes],
+           [fu_cv_sys_mounted_getextmntent=no])])
+      if test $fu_cv_sys_mounted_getextmntent = yes; then
+        ac_list_mounted_fs=found
+        AC_DEFINE([MOUNTED_GETEXTMNTENT], [1],
+          [Define if there is a function named getextmntent for reading the list
+           of mounted file systems.  (Solaris)])
+      fi
+    fi
+
+    if test -z "$ac_list_mounted_fs"; then
+      # Solaris < 8, also (obsolete) SVR4.
+      # Solaris >= 8 has the two-argument getmntent but is already handled above.
+      AC_CACHE_CHECK([for two-argument getmntent function],
+        [fu_cv_sys_mounted_getmntent2],
+        [AC_EGREP_HEADER([getmntent], [sys/mnttab.h],
+           [fu_cv_sys_mounted_getmntent2=yes],
+           [fu_cv_sys_mounted_getmntent2=no])
+        ])
+      if test $fu_cv_sys_mounted_getmntent2 = yes; then
+        ac_list_mounted_fs=found
+        AC_DEFINE([MOUNTED_GETMNTENT2], [1],
+          [Define if there is a function named getmntent for reading the list of
+           mounted file systems, and that function takes two arguments.  (SVR4)])
+        AC_CHECK_FUNCS([hasmntopt])
+      fi
+    fi
+
+  fi
+
+  if test -z "$ac_list_mounted_fs"; then
+    # OSF/1, also (obsolete) Apple Darwin 1.3.
+    # powerpc-apple-darwin1.3.7 needs sys/param.h sys/ucred.h sys/fs_types.h
+
+    AC_CACHE_CHECK([for getfsstat function],
+      [fu_cv_sys_mounted_getfsstat],
+      [AC_LINK_IFELSE(
+         [AC_LANG_PROGRAM([[
+#include <sys/types.h>
+#if HAVE_STRUCT_FSSTAT_F_FSTYPENAME
+# define FS_TYPE(Ent) ((Ent).f_fstypename)
+#else
+# define FS_TYPE(Ent) mnt_names[(Ent).f_type]
+#endif
+$getfsstat_includes
+            ]],
+            [[struct statfs *stats;
+              int numsys = getfsstat ((struct statfs *)0, 0L, MNT_WAIT);
+              char *t = FS_TYPE (*stats);
+            ]])],
+         [fu_cv_sys_mounted_getfsstat=yes],
+         [fu_cv_sys_mounted_getfsstat=no])
+      ])
+    if test $fu_cv_sys_mounted_getfsstat = yes; then
+      ac_list_mounted_fs=found
+      AC_DEFINE([MOUNTED_GETFSSTAT], [1],
+        [Define if there is a function named getfsstat for reading the
+         list of mounted file systems.  (DEC Alpha running OSF/1)])
+    fi
+  fi
+
+  if test -z "$ac_list_mounted_fs"; then
+    # (obsolete) SVR3
+    AC_CACHE_CHECK([for FIXME existence of three headers],
+      [fu_cv_sys_mounted_fread_fstyp],
+      [AC_PREPROC_IFELSE([AC_LANG_SOURCE([[
+#include <sys/statfs.h>
+#include <sys/fstyp.h>
+#include <mnttab.h>
+]])],
+         [fu_cv_sys_mounted_fread_fstyp=yes],
+         [fu_cv_sys_mounted_fread_fstyp=no])
+      ])
+    if test $fu_cv_sys_mounted_fread_fstyp = yes; then
+      ac_list_mounted_fs=found
+      AC_DEFINE([MOUNTED_FREAD_FSTYP], [1],
+        [Define if (like SVR2) there is no specific function for reading the
+         list of mounted file systems, and your system has these header files:
+         <sys/fstyp.h> and <sys/statfs.h>.  (SVR3)])
+    fi
+  fi
+
+  if test -z "$ac_list_mounted_fs"; then
+    # Mac OS X, FreeBSD, NetBSD, OpenBSD, Minix, also (obsolete) 4.4BSD.
+    # OSF/1 also has getmntinfo but is already handled above.
+    # We cannot use AC_CHECK_FUNCS([getmntinfo]) here, because at the linker
+    # level the function is sometimes called getmntinfo64 or getmntinfo$INODE64
+    # on Mac OS X, __getmntinfo13 on NetBSD and Minix, _F64_getmntinfo on OSF/1.
+    AC_CACHE_CHECK([for getmntinfo function],
+      [fu_cv_sys_mounted_getmntinfo],
+      [AC_LINK_IFELSE(
+         [AC_LANG_PROGRAM([[
+#if HAVE_SYS_PARAM_H
+# include <sys/param.h>
+#endif
+#include <sys/types.h>
+#if HAVE_SYS_MOUNT_H
+# include <sys/mount.h>
+#endif
+#if HAVE_SYS_STATVFS_H
+# include <sys/statvfs.h>
+#endif
+#include <stdlib.h>
+            ]],
+            [[int count = getmntinfo (NULL, MNT_WAIT);
+            ]])],
+         [fu_cv_sys_mounted_getmntinfo=yes],
+         [fu_cv_sys_mounted_getmntinfo=no])
+      ])
+    if test $fu_cv_sys_mounted_getmntinfo = yes; then
+      AC_CACHE_CHECK([whether getmntinfo returns statvfs structures],
+        [fu_cv_sys_mounted_getmntinfo2],
+        [AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM([[
+#if HAVE_SYS_PARAM_H
+# include <sys/param.h>
+#endif
+#include <sys/types.h>
+#if HAVE_SYS_MOUNT_H
+# include <sys/mount.h>
+#endif
+#if HAVE_SYS_STATVFS_H
+# include <sys/statvfs.h>
+#endif
+extern
+#ifdef __cplusplus
+"C"
+#endif
+int getmntinfo (struct statfs **, int);
+              ]], [[]])],
+           [fu_cv_sys_mounted_getmntinfo2=no],
+           [fu_cv_sys_mounted_getmntinfo2=yes])
+        ])
+      if test $fu_cv_sys_mounted_getmntinfo2 = no; then
+        # Mac OS X, FreeBSD, OpenBSD, also (obsolete) 4.4BSD.
+        ac_list_mounted_fs=found
+        AC_DEFINE([MOUNTED_GETMNTINFO], [1],
+          [Define if there is a function named getmntinfo for reading the
+           list of mounted file systems and it returns an array of
+           'struct statfs'.  (4.4BSD, Darwin)])
+      else
+        # NetBSD, Minix.
+        ac_list_mounted_fs=found
+        AC_DEFINE([MOUNTED_GETMNTINFO2], [1],
+          [Define if there is a function named getmntinfo for reading the
+           list of mounted file systems and it returns an array of
+           'struct statvfs'.  (NetBSD 3.0)])
+      fi
+    fi
+  fi
+
+  if test -z "$ac_list_mounted_fs"; then
+    # Haiku, also (obsolete) BeOS.
+    AC_CHECK_FUNCS([next_dev fs_stat_dev])
+    AC_CHECK_HEADERS([fs_info.h])
+    AC_CACHE_CHECK([for BEOS mounted file system support functions],
+      [fu_cv_sys_mounted_fs_stat_dev],
+      [if test $ac_cv_header_fs_info_h = yes \
+          && test $ac_cv_func_next_dev = yes \
+          && test $ac_cv_func_fs_stat_dev = yes; then
+         fu_cv_sys_mounted_fs_stat_dev=yes
+       else
+         fu_cv_sys_mounted_fs_stat_dev=no
+       fi
+      ])
+    if test $fu_cv_sys_mounted_fs_stat_dev = yes; then
+      ac_list_mounted_fs=found
+      AC_DEFINE([MOUNTED_FS_STAT_DEV], [1],
+        [Define if there are functions named next_dev and fs_stat_dev for
+         reading the list of mounted file systems.  (BeOS)])
+    fi
+  fi
+
+  if test -z "$ac_list_mounted_fs"; then
+    # Interix / BSD alike statvfs
+    # the code is really interix specific, so make sure, we're on it.
+    case "$host" in
+      *-interix*)
+        AC_CHECK_FUNCS([statvfs])
+        if test $ac_cv_func_statvfs = yes; then
+          ac_list_mounted_fs=found
+          AC_DEFINE([MOUNTED_INTERIX_STATVFS], [1],
+            [Define if we are on interix, and ought to use statvfs plus
+             some special knowledge on where mounted file systems can be
+             found. (Interix)])
+        fi
+        ;;
+    esac
+  fi
+
+  if test -z "$ac_list_mounted_fs"; then
+    AC_MSG_ERROR([could not determine how to read list of mounted file systems])
+    # FIXME -- no need to abort building the whole package
+    # Can't build mountlist.c or anything that needs its functions
+  fi
+
+  if test $ac_list_mounted_fs = found; then
+    gl_cv_list_mounted_fs=yes
+  else
+    gl_cv_list_mounted_fs=no
+  fi
 ])
 
-# Prerequisites of lib/mountlist.c not done by gl_LIST_MOUNTED_FILE_SYSTEMS.
+# Prerequisites of lib/mountlist.c not done by gl_MOUNTLIST.
 AC_DEFUN([gl_PREREQ_MOUNTLIST_EXTRA],
 [
-  dnl Note gl_LIST_MOUNTED_FILE_SYSTEMS checks for mntent.h, not sys/mntent.h.
+  dnl Note gl_MOUNTLIST checks for mntent.h, not sys/mntent.h.
   AC_CHECK_HEADERS([sys/mntent.h])
+  AC_HEADER_MAJOR()dnl for use of makedev ()
   gl_FSTYPENAME
 ])
+
+# Replace Autoconf's AC_FUNC_GETMNTENT to omit checks that are unnecessary
+# nowadays.
+AC_DEFUN([AC_FUNC_GETMNTENT],
+[
+  # getmntent is in the standard C library on most systems, but in -lgen on
+  # Unixware.
+  AC_SEARCH_LIBS([getmntent], [gen])
+  AC_CHECK_FUNCS([getmntent])
+])
diff --git a/gl/m4/msvc-inval.m4 b/gl/m4/msvc-inval.m4
index 9a6a47a7..8d9d21b5 100644
--- a/gl/m4/msvc-inval.m4
+++ b/gl/m4/msvc-inval.m4
@@ -1,5 +1,5 @@
 # msvc-inval.m4 serial 1
-dnl Copyright (C) 2011-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2011-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/msvc-nothrow.m4 b/gl/m4/msvc-nothrow.m4
index a39618a4..0263e490 100644
--- a/gl/m4/msvc-nothrow.m4
+++ b/gl/m4/msvc-nothrow.m4
@@ -1,5 +1,5 @@
 # msvc-nothrow.m4 serial 1
-dnl Copyright (C) 2011-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2011-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/multiarch.m4 b/gl/m4/multiarch.m4
index 552ec7e7..3ba5b0f7 100644
--- a/gl/m4/multiarch.m4
+++ b/gl/m4/multiarch.m4
@@ -1,5 +1,5 @@
-# multiarch.m4 serial 7
-dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
+# multiarch.m4 serial 9
+dnl Copyright (C) 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -21,37 +21,40 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN_ONCE([gl_MULTIARCH],
 [
   dnl Code similar to autoconf-2.63 AC_C_BIGENDIAN.
-  gl_cv_c_multiarch=no
-  AC_COMPILE_IFELSE(
-    [AC_LANG_SOURCE(
-      [[#ifndef __APPLE_CC__
-         not a universal capable compiler
-        #endif
-        typedef int dummy;
-      ]])],
-    [
-     dnl Check for potential -arch flags.  It is not universal unless
-     dnl there are at least two -arch flags with different values.
-     arch=
-     prev=
-     for word in ${CC} ${CFLAGS} ${CPPFLAGS} ${LDFLAGS}; do
-       if test -n "$prev"; then
-         case $word in
-           i?86 | x86_64 | ppc | ppc64)
-             if test -z "$arch" || test "$arch" = "$word"; then
-               arch="$word"
-             else
-               gl_cv_c_multiarch=yes
-             fi
-             ;;
-         esac
-         prev=
-       else
-         if test "x$word" = "x-arch"; then
-           prev=arch
-         fi
-       fi
-     done
+  AC_CACHE_CHECK([whether the compiler produces multi-arch binaries],
+    [gl_cv_c_multiarch],
+    [gl_cv_c_multiarch=no
+     AC_COMPILE_IFELSE(
+       [AC_LANG_SOURCE(
+         [[#ifndef __APPLE_CC__
+            not a universal capable compiler
+           #endif
+           typedef int dummy;
+         ]])],
+       [
+        dnl Check for potential -arch flags.  It is not universal unless
+        dnl there are at least two -arch flags with different values.
+        arch=
+        prev=
+        for word in ${CC} ${CFLAGS} ${CPPFLAGS} ${LDFLAGS}; do
+          if test -n "$prev"; then
+            case $word in
+              i?86 | x86_64 | ppc | ppc64 | arm | arm64)
+                if test -z "$arch" || test "$arch" = "$word"; then
+                  arch="$word"
+                else
+                  gl_cv_c_multiarch=yes
+                fi
+                ;;
+            esac
+            prev=
+          else
+            if test "x$word" = "x-arch"; then
+              prev=arch
+            fi
+          fi
+        done
+       ])
     ])
   if test $gl_cv_c_multiarch = yes; then
     APPLE_UNIVERSAL_BUILD=1
diff --git a/gl/m4/netdb_h.m4 b/gl/m4/netdb_h.m4
index 2c69f999..e6aa8925 100644
--- a/gl/m4/netdb_h.m4
+++ b/gl/m4/netdb_h.m4
@@ -1,10 +1,10 @@
-# netdb_h.m4 serial 11
-dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
+# netdb_h.m4 serial 15
+dnl Copyright (C) 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-AC_DEFUN([gl_HEADER_NETDB],
+AC_DEFUN_ONCE([gl_NETDB_H],
 [
   AC_REQUIRE([gl_NETDB_H_DEFAULTS])
   gl_CHECK_NEXT_HEADERS([netdb.h])
@@ -21,18 +21,33 @@ AC_DEFUN([gl_HEADER_NETDB],
     [getaddrinfo freeaddrinfo gai_strerror getnameinfo])
 ])
 
+# gl_NETDB_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_NETDB_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_NETDB_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_NETDB_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_NETDB_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_NETDB_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETADDRINFO])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_NETDB_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_NETDB_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_NETDB_H_DEFAULTS],
 [
-  GNULIB_GETADDRINFO=0; AC_SUBST([GNULIB_GETADDRINFO])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_STRUCT_ADDRINFO=1;   AC_SUBST([HAVE_STRUCT_ADDRINFO])
   HAVE_DECL_FREEADDRINFO=1; AC_SUBST([HAVE_DECL_FREEADDRINFO])
@@ -40,4 +55,5 @@ AC_DEFUN([gl_NETDB_H_DEFAULTS],
   HAVE_DECL_GETADDRINFO=1;  AC_SUBST([HAVE_DECL_GETADDRINFO])
   HAVE_DECL_GETNAMEINFO=1;  AC_SUBST([HAVE_DECL_GETNAMEINFO])
   REPLACE_GAI_STRERROR=0;   AC_SUBST([REPLACE_GAI_STRERROR])
+  REPLACE_GETADDRINFO=0;    AC_SUBST([REPLACE_GETADDRINFO])
 ])
diff --git a/gl/m4/netinet_in_h.m4 b/gl/m4/netinet_in_h.m4
index 21971b29..71154191 100644
--- a/gl/m4/netinet_in_h.m4
+++ b/gl/m4/netinet_in_h.m4
@@ -1,5 +1,5 @@
-# netinet_in_h.m4 serial 5
-dnl Copyright (C) 2006-2013 Free Software Foundation, Inc.
+# netinet_in_h.m4 serial 6
+dnl Copyright (C) 2006-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -14,9 +14,9 @@ AC_DEFUN([gl_HEADER_NETINET_IN],
         [gl_cv_header_netinet_in_h_selfcontained=no])
     ])
   if test $gl_cv_header_netinet_in_h_selfcontained = yes; then
-    NETINET_IN_H=''
+    GL_GENERATE_NETINET_IN_H=false
   else
-    NETINET_IN_H='netinet/in.h'
+    GL_GENERATE_NETINET_IN_H=true
     AC_CHECK_HEADERS([netinet/in.h])
     gl_CHECK_NEXT_HEADERS([netinet/in.h])
     if test $ac_cv_header_netinet_in_h = yes; then
@@ -26,6 +26,4 @@ AC_DEFUN([gl_HEADER_NETINET_IN],
     fi
     AC_SUBST([HAVE_NETINET_IN_H])
   fi
-  AC_SUBST([NETINET_IN_H])
-  AM_CONDITIONAL([GL_GENERATE_NETINET_IN_H], [test -n "$NETINET_IN_H"])
 ])
diff --git a/gl/m4/nl_langinfo.m4 b/gl/m4/nl_langinfo.m4
index 25e21015..51e783ce 100644
--- a/gl/m4/nl_langinfo.m4
+++ b/gl/m4/nl_langinfo.m4
@@ -1,5 +1,5 @@
-# nl_langinfo.m4 serial 5
-dnl Copyright (C) 2009-2013 Free Software Foundation, Inc.
+# nl_langinfo.m4 serial 8
+dnl Copyright (C) 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -9,7 +9,10 @@ AC_DEFUN([gl_FUNC_NL_LANGINFO],
   AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
   AC_REQUIRE([gl_LANGINFO_H])
   AC_CHECK_FUNCS_ONCE([nl_langinfo])
-  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_FUNC_SETLOCALE_NULL])
+  AC_REQUIRE([gl_PTHREADLIB])
+  AC_CHECK_HEADERS_ONCE([threads.h])
   if test $ac_cv_func_nl_langinfo = yes; then
     # On Irix 6.5, YESEXPR is defined, but nl_langinfo(YESEXPR) is broken.
     AC_CACHE_CHECK([whether YESEXPR works],
@@ -36,8 +39,19 @@ AC_DEFUN([gl_FUNC_NL_LANGINFO],
     AC_DEFINE_UNQUOTED([FUNC_NL_LANGINFO_YESEXPR_WORKS],
       [$FUNC_NL_LANGINFO_YESEXPR_WORKS],
       [Define to 1 if nl_langinfo (YESEXPR) returns a non-empty string.])
-    if test $HAVE_LANGINFO_CODESET = 1 && test $HAVE_LANGINFO_ERA = 1 \
-        && test $FUNC_NL_LANGINFO_YESEXPR_WORKS = 1; then
+    # On Solaris 10 and Solaris 11.3, nl_langinfo is not multithread-safe.
+    case "$host_os" in
+      solaris*) NL_LANGINFO_MTSAFE=0 ;;
+      *)        NL_LANGINFO_MTSAFE=1 ;;
+    esac
+    AC_DEFINE_UNQUOTED([NL_LANGINFO_MTSAFE], [$NL_LANGINFO_MTSAFE],
+      [Define to 1 if nl_langinfo is multithread-safe.])
+    if test $HAVE_LANGINFO_CODESET = 1 \
+       && test $HAVE_LANGINFO_T_FMT_AMPM = 1 \
+       && test $HAVE_LANGINFO_ALTMON = 1 \
+       && test $HAVE_LANGINFO_ERA = 1 \
+       && test $FUNC_NL_LANGINFO_YESEXPR_WORKS = 1 \
+       && test $NL_LANGINFO_MTSAFE = 1; then
       :
     else
       REPLACE_NL_LANGINFO=1
@@ -47,4 +61,17 @@ AC_DEFUN([gl_FUNC_NL_LANGINFO],
   else
     HAVE_NL_LANGINFO=0
   fi
+  if test $HAVE_NL_LANGINFO = 0 || test $HAVE_LANGINFO_CODESET = 0; then
+    LIB_NL_LANGINFO="$LIB_SETLOCALE_NULL"
+  else
+    LIB_NL_LANGINFO=
+  fi
+  dnl LIB_NL_LANGINFO is expected to be empty everywhere.
+  AC_SUBST([LIB_NL_LANGINFO])
+])
+
+# Prerequisites of lib/nl_langinfo-lock.c.
+AC_DEFUN([gl_PREREQ_NL_LANGINFO_LOCK],
+[
+  gl_VISIBILITY
 ])
diff --git a/gl/m4/nls.m4 b/gl/m4/nls.m4
index 8f8a147b..65724481 100644
--- a/gl/m4/nls.m4
+++ b/gl/m4/nls.m4
@@ -1,17 +1,17 @@
-# nls.m4 serial 5 (gettext-0.18)
-dnl Copyright (C) 1995-2003, 2005-2006, 2008-2013 Free Software Foundation,
-dnl Inc.
+# nls.m4 serial 6 (gettext-0.20.2)
+dnl Copyright (C) 1995-2003, 2005-2006, 2008-2014, 2016, 2019-2023 Free
+dnl Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 dnl
-dnl This file can can be used in projects which are not available under
-dnl the GNU General Public License or the GNU Library General Public
+dnl This file can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Lesser General Public
 dnl License but which still want to provide support for the GNU gettext
 dnl functionality.
 dnl Please note that the actual code of the GNU gettext library is covered
-dnl by the GNU Library General Public License, and the rest of the GNU
-dnl gettext package package is covered by the GNU General Public License.
+dnl by the GNU Lesser General Public License, and the rest of the GNU
+dnl gettext package is covered by the GNU General Public License.
 dnl They are *not* in the public domain.
 
 dnl Authors:
diff --git a/gl/m4/nocrash.m4 b/gl/m4/nocrash.m4
index 105b884f..6a766387 100644
--- a/gl/m4/nocrash.m4
+++ b/gl/m4/nocrash.m4
@@ -1,5 +1,5 @@
-# nocrash.m4 serial 4
-dnl Copyright (C) 2005, 2009-2013 Free Software Foundation, Inc.
+# nocrash.m4 serial 5
+dnl Copyright (C) 2005, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -53,7 +53,7 @@ nocrash_init (void)
   /* Allocate a port on which the thread shall listen for exceptions.  */
   if (mach_port_allocate (self, MACH_PORT_RIGHT_RECEIVE, &our_exception_port)
       == KERN_SUCCESS) {
-    /* See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/mach_port_insert_right.html.  */
+    /* See https://web.mit.edu/darwin/src/modules/xnu/osfmk/man/mach_port_insert_right.html.  */
     if (mach_port_insert_right (self, our_exception_port, our_exception_port,
                                 MACH_MSG_TYPE_MAKE_SEND)
         == KERN_SUCCESS) {
@@ -72,14 +72,14 @@ nocrash_init (void)
            for a particular thread.  This has the effect that when our exception
            port gets the message, the thread specific exception port has already
            been asked, and we don't need to bother about it.
-           See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/task_set_exception_ports.html.  */
+           See https://web.mit.edu/darwin/src/modules/xnu/osfmk/man/task_set_exception_ports.html.  */
         task_set_exception_ports (self, mask, our_exception_port,
                                   EXCEPTION_DEFAULT, MACHINE_THREAD_STATE);
       }
     }
   }
 }
-#elif (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+#elif defined _WIN32 && ! defined __CYGWIN__
 /* Avoid a crash on native Windows.  */
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
@@ -110,11 +110,12 @@ nocrash_init (void)
 #else
 /* Avoid a crash on POSIX systems.  */
 #include <signal.h>
+#include <unistd.h>
 /* A POSIX signal handler.  */
 static void
 exception_handler (int sig)
 {
-  exit (1);
+  _exit (1);
 }
 static void
 nocrash_init (void)
diff --git a/gl/m4/off_t.m4 b/gl/m4/off_t.m4
index d355d013..880f3472 100644
--- a/gl/m4/off_t.m4
+++ b/gl/m4/off_t.m4
@@ -1,5 +1,5 @@
 # off_t.m4 serial 1
-dnl Copyright (C) 2012-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2012-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/onceonly.m4 b/gl/m4/onceonly.m4
deleted file mode 100644
index 0a875a3d..00000000
--- a/gl/m4/onceonly.m4
+++ /dev/null
@@ -1,104 +0,0 @@
-# onceonly.m4 serial 9
-dnl Copyright (C) 2002-2003, 2005-2006, 2008-2013 Free Software Foundation,
-dnl Inc.
-dnl
-dnl This file is free software; you can redistribute it and/or modify
-dnl it under the terms of the GNU General Public License as published by
-dnl the Free Software Foundation; either version 3 of the License, or
-dnl (at your option) any later version.
-dnl
-dnl This file is distributed in the hope that it will be useful,
-dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
-dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-dnl GNU General Public License for more details.
-dnl
-dnl You should have received a copy of the GNU General Public License
-dnl along with this file.  If not, see <http://www.gnu.org/licenses/>.
-dnl
-dnl As a special exception to the GNU General Public License,
-dnl this file may be distributed as part of a program
-dnl that contains a configuration script generated by Autoconf, under
-dnl the same distribution terms as the rest of that program.
-
-dnl This file defines some "once only" variants of standard autoconf macros.
-dnl   AC_CHECK_HEADERS_ONCE          like  AC_CHECK_HEADERS
-dnl   AC_CHECK_FUNCS_ONCE            like  AC_CHECK_FUNCS
-dnl   AC_CHECK_DECLS_ONCE            like  AC_CHECK_DECLS
-dnl   AC_REQUIRE([AC_FUNC_STRCOLL])  like  AC_FUNC_STRCOLL
-dnl The advantage is that the check for each of the headers/functions/decls
-dnl will be put only once into the 'configure' file. It keeps the size of
-dnl the 'configure' file down, and avoids redundant output when 'configure'
-dnl is run.
-dnl The drawback is that the checks cannot be conditionalized. If you write
-dnl   if some_condition; then gl_CHECK_HEADERS(stdlib.h); fi
-dnl inside an AC_DEFUNed function, the gl_CHECK_HEADERS macro call expands to
-dnl empty, and the check will be inserted before the body of the AC_DEFUNed
-dnl function.
-
-dnl The original code implemented AC_CHECK_HEADERS_ONCE and AC_CHECK_FUNCS_ONCE
-dnl in terms of AC_DEFUN and AC_REQUIRE. This implementation uses diversions to
-dnl named sections DEFAULTS and INIT_PREPARE in order to check all requested
-dnl headers at once, thus reducing the size of 'configure'. It is known to work
-dnl with autoconf 2.57..2.62 at least . The size reduction is ca. 9%.
-
-dnl Autoconf version 2.59 plus gnulib is required; this file is not needed
-dnl with Autoconf 2.60 or greater. But note that autoconf's implementation of
-dnl AC_CHECK_DECLS_ONCE expects a comma-separated list of symbols as first
-dnl argument!
-AC_PREREQ([2.59])
-
-# AC_CHECK_HEADERS_ONCE(HEADER1 HEADER2 ...) is a once-only variant of
-# AC_CHECK_HEADERS(HEADER1 HEADER2 ...).
-AC_DEFUN([AC_CHECK_HEADERS_ONCE], [
-  :
-  m4_foreach_w([gl_HEADER_NAME], [$1], [
-    AC_DEFUN([gl_CHECK_HEADER_]m4_quote(m4_translit(gl_HEADER_NAME,
-                                                    [./-], [___])), [
-      m4_divert_text([INIT_PREPARE],
-        [gl_header_list="$gl_header_list gl_HEADER_NAME"])
-      gl_HEADERS_EXPANSION
-      AH_TEMPLATE(AS_TR_CPP([HAVE_]m4_defn([gl_HEADER_NAME])),
-        [Define to 1 if you have the <]m4_defn([gl_HEADER_NAME])[> header file.])
-    ])
-    AC_REQUIRE([gl_CHECK_HEADER_]m4_quote(m4_translit(gl_HEADER_NAME,
-                                                      [./-], [___])))
-  ])
-])
-m4_define([gl_HEADERS_EXPANSION], [
-  m4_divert_text([DEFAULTS], [gl_header_list=])
-  AC_CHECK_HEADERS([$gl_header_list])
-  m4_define([gl_HEADERS_EXPANSION], [])
-])
-
-# AC_CHECK_FUNCS_ONCE(FUNC1 FUNC2 ...) is a once-only variant of
-# AC_CHECK_FUNCS(FUNC1 FUNC2 ...).
-AC_DEFUN([AC_CHECK_FUNCS_ONCE], [
-  :
-  m4_foreach_w([gl_FUNC_NAME], [$1], [
-    AC_DEFUN([gl_CHECK_FUNC_]m4_defn([gl_FUNC_NAME]), [
-      m4_divert_text([INIT_PREPARE],
-        [gl_func_list="$gl_func_list gl_FUNC_NAME"])
-      gl_FUNCS_EXPANSION
-      AH_TEMPLATE(AS_TR_CPP([HAVE_]m4_defn([gl_FUNC_NAME])),
-        [Define to 1 if you have the ']m4_defn([gl_FUNC_NAME])[' function.])
-    ])
-    AC_REQUIRE([gl_CHECK_FUNC_]m4_defn([gl_FUNC_NAME]))
-  ])
-])
-m4_define([gl_FUNCS_EXPANSION], [
-  m4_divert_text([DEFAULTS], [gl_func_list=])
-  AC_CHECK_FUNCS([$gl_func_list])
-  m4_define([gl_FUNCS_EXPANSION], [])
-])
-
-# AC_CHECK_DECLS_ONCE(DECL1 DECL2 ...) is a once-only variant of
-# AC_CHECK_DECLS(DECL1, DECL2, ...).
-AC_DEFUN([AC_CHECK_DECLS_ONCE], [
-  :
-  m4_foreach_w([gl_DECL_NAME], [$1], [
-    AC_DEFUN([gl_CHECK_DECL_]m4_defn([gl_DECL_NAME]), [
-      AC_CHECK_DECLS(m4_defn([gl_DECL_NAME]))
-    ])
-    AC_REQUIRE([gl_CHECK_DECL_]m4_defn([gl_DECL_NAME]))
-  ])
-])
diff --git a/gl/m4/open-cloexec.m4 b/gl/m4/open-cloexec.m4
new file mode 100644
index 00000000..fd572fcd
--- /dev/null
+++ b/gl/m4/open-cloexec.m4
@@ -0,0 +1,21 @@
+# Test whether O_CLOEXEC is defined.
+
+dnl Copyright 2017-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_PREPROC_O_CLOEXEC],
+[
+  AC_CACHE_CHECK([for O_CLOEXEC],
+    [gl_cv_macro_O_CLOEXEC],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM([[#include <fcntl.h>
+                          #ifndef O_CLOEXEC
+                            choke me;
+                          #endif
+                        ]],
+                        [[return O_CLOEXEC;]])],
+       [gl_cv_macro_O_CLOEXEC=yes],
+       [gl_cv_macro_O_CLOEXEC=no])])
+])
diff --git a/gl/m4/open-slash.m4 b/gl/m4/open-slash.m4
new file mode 100644
index 00000000..1f731f8a
--- /dev/null
+++ b/gl/m4/open-slash.m4
@@ -0,0 +1,60 @@
+# open-slash.m4 serial 2
+dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Tests whether open() and creat() recognize a trailing slash.
+dnl Sets gl_cv_func_open_slash.
+AC_DEFUN([gl_OPEN_TRAILING_SLASH_BUG],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  dnl open("foo/") should not create a file when the file name has a
+  dnl trailing slash.  FreeBSD only has the problem on symlinks.
+  AC_CHECK_FUNCS_ONCE([lstat])
+  AC_CACHE_CHECK([whether open recognizes a trailing slash],
+    [gl_cv_func_open_slash],
+    [# Assume that if we have lstat, we can also check symlinks.
+     if test $ac_cv_func_lstat = yes; then
+       touch conftest.tmp
+       ln -s conftest.tmp conftest.lnk
+     fi
+     AC_RUN_IFELSE(
+       [AC_LANG_SOURCE([[
+#include <fcntl.h>
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+]GL_MDA_DEFINES[
+int main ()
+{
+  int result = 0;
+#if HAVE_LSTAT
+  if (open ("conftest.lnk/", O_RDONLY) != -1)
+    result |= 1;
+#endif
+  if (open ("conftest.sl/", O_CREAT, 0600) >= 0)
+    result |= 2;
+  return result;
+}]])],
+       [gl_cv_func_open_slash=yes],
+       [gl_cv_func_open_slash=no],
+       [
+changequote(,)dnl
+        case "$host_os" in
+          freebsd* | aix* | hpux* | solaris2.[0-9] | solaris2.[0-9].*)
+            gl_cv_func_open_slash="guessing no" ;;
+          *)
+            gl_cv_func_open_slash="guessing yes" ;;
+        esac
+changequote([,])dnl
+       ])
+     rm -f conftest.sl conftest.tmp conftest.lnk
+    ])
+  case "$gl_cv_func_open_slash" in
+    *no)
+      AC_DEFINE([OPEN_TRAILING_SLASH_BUG], [1],
+        [Define to 1 if open() fails to recognize a trailing slash.])
+      ;;
+  esac
+])
diff --git a/gl/m4/open.m4 b/gl/m4/open.m4
new file mode 100644
index 00000000..94fa2bb7
--- /dev/null
+++ b/gl/m4/open.m4
@@ -0,0 +1,56 @@
+# open.m4 serial 15
+dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_OPEN],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_PREPROC_O_CLOEXEC])
+  case "$host_os" in
+    mingw* | pw*)
+      REPLACE_OPEN=1
+      ;;
+    *)
+      dnl open("foo/") should not create a file when the file name has a
+      dnl trailing slash.  FreeBSD only has the problem on symlinks.
+      AC_CHECK_FUNCS_ONCE([lstat])
+      if test "$gl_cv_macro_O_CLOEXEC" != yes; then
+        REPLACE_OPEN=1
+      fi
+      gl_OPEN_TRAILING_SLASH_BUG
+      case "$gl_cv_func_open_slash" in
+        *no)
+          REPLACE_OPEN=1
+          ;;
+      esac
+      ;;
+  esac
+  dnl Replace open() for supporting the gnulib-defined fchdir() function,
+  dnl to keep fchdir's bookkeeping up-to-date.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    if test $REPLACE_OPEN = 0; then
+      gl_TEST_FCHDIR
+      if test $HAVE_FCHDIR = 0; then
+        REPLACE_OPEN=1
+      fi
+    fi
+  ])
+  dnl Replace open() for supporting the gnulib-defined O_NONBLOCK flag.
+  m4_ifdef([gl_NONBLOCKING_IO], [
+    if test $REPLACE_OPEN = 0; then
+      gl_NONBLOCKING_IO
+      if test $gl_cv_have_open_O_NONBLOCK != yes; then
+        REPLACE_OPEN=1
+      fi
+    fi
+  ])
+])
+
+# Prerequisites of lib/open.c.
+AC_DEFUN([gl_PREREQ_OPEN],
+[
+  AC_REQUIRE([gl_PROMOTED_TYPE_MODE_T])
+  :
+])
diff --git a/gl/m4/pathmax.m4 b/gl/m4/pathmax.m4
new file mode 100644
index 00000000..6d47d2c0
--- /dev/null
+++ b/gl/m4/pathmax.m4
@@ -0,0 +1,42 @@
+# pathmax.m4 serial 11
+dnl Copyright (C) 2002-2003, 2005-2006, 2009-2023 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_PATHMAX],
+[
+  dnl Prerequisites of lib/pathmax.h.
+  AC_CHECK_HEADERS_ONCE([sys/param.h])
+])
+
+# Expands to a piece of C program that defines PATH_MAX in the same way as
+# "pathmax.h" will do.
+AC_DEFUN([gl_PATHMAX_SNIPPET], [[
+/* Arrange to define PATH_MAX, like "pathmax.h" does. */
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+#include <limits.h>
+#if defined HAVE_SYS_PARAM_H && !defined PATH_MAX && !defined MAXPATHLEN
+# include <sys/param.h>
+#endif
+#if !defined PATH_MAX && defined MAXPATHLEN
+# define PATH_MAX MAXPATHLEN
+#endif
+#ifdef __hpux
+# undef PATH_MAX
+# define PATH_MAX 1024
+#endif
+#if defined _WIN32 && ! defined __CYGWIN__
+# undef PATH_MAX
+# define PATH_MAX 260
+#endif
+]])
+
+# Prerequisites of gl_PATHMAX_SNIPPET.
+AC_DEFUN([gl_PATHMAX_SNIPPET_PREREQ],
+[
+  AC_CHECK_HEADERS_ONCE([unistd.h sys/param.h])
+])
diff --git a/gl/m4/pid_t.m4 b/gl/m4/pid_t.m4
new file mode 100644
index 00000000..0fd7d0a1
--- /dev/null
+++ b/gl/m4/pid_t.m4
@@ -0,0 +1,38 @@
+# pid_t.m4 serial 4
+dnl Copyright (C) 2020-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# The following implementation works around a problem in autoconf <= 2.69.
+m4_version_prereq([2.70], [], [
+
+dnl Define pid_t if the headers don't define it.
+AC_DEFUN([AC_TYPE_PID_T],
+[
+  AC_CHECK_TYPE([pid_t],
+    [],
+    [dnl On 64-bit native Windows, define it to the equivalent of 'intptr_t'
+     dnl (= 'long long' = '__int64'), because that is the return type
+     dnl of the _spawnv* functions
+     dnl <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/spawnvp-wspawnvp>
+     dnl and the argument type of the _cwait function
+     dnl <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/cwait>.
+     dnl Otherwise (on 32-bit Windows and on old Unix platforms), define it
+     dnl to 'int'.
+     AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM([[
+          #if defined _WIN64 && !defined __CYGWIN__
+          LLP64
+          #endif
+          ]])
+       ],
+       [gl_pid_type='int'],
+       [gl_pid_type='__int64'])
+     AC_DEFINE_UNQUOTED([pid_t], [$gl_pid_type],
+       [Define as a signed integer type capable of holding a process identifier.])
+    ],
+    [AC_INCLUDES_DEFAULT])
+])
+
+])# m4_version_prereq 2.70
diff --git a/gl/m4/po.m4 b/gl/m4/po.m4
index 1c70b6c1..26a5a6f5 100644
--- a/gl/m4/po.m4
+++ b/gl/m4/po.m4
@@ -1,16 +1,16 @@
-# po.m4 serial 21 (gettext-0.18.3)
-dnl Copyright (C) 1995-2013 Free Software Foundation, Inc.
+# po.m4 serial 31 (gettext-0.20.2)
+dnl Copyright (C) 1995-2014, 2016, 2018-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 dnl
-dnl This file can can be used in projects which are not available under
-dnl the GNU General Public License or the GNU Library General Public
+dnl This file can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Lesser General Public
 dnl License but which still want to provide support for the GNU gettext
 dnl functionality.
 dnl Please note that the actual code of the GNU gettext library is covered
-dnl by the GNU Library General Public License, and the rest of the GNU
-dnl gettext package package is covered by the GNU General Public License.
+dnl by the GNU Lesser General Public License, and the rest of the GNU
+dnl gettext package is covered by the GNU General Public License.
 dnl They are *not* in the public domain.
 
 dnl Authors:
@@ -30,7 +30,7 @@ AC_DEFUN([AM_PO_SUBDIRS],
 
   dnl Release version of the gettext macros. This is used to ensure that
   dnl the gettext macros and po/Makefile.in.in are in sync.
-  AC_SUBST([GETTEXT_MACRO_VERSION], [0.18])
+  AC_SUBST([GETTEXT_MACRO_VERSION], [0.20])
 
   dnl Perform the following tests also if --disable-nls has been given,
   dnl because they are needed for "make dist" to work.
@@ -46,13 +46,6 @@ AC_DEFUN([AM_PO_SUBDIRS],
 
   dnl Test whether it is GNU msgfmt >= 0.15.
 changequote(,)dnl
-  case `$MSGFMT --version | sed 1q | sed -e 's,^[^0-9]*,,'` in
-    '' | 0.[0-9] | 0.[0-9].* | 0.1[0-4] | 0.1[0-4].*) MSGFMT_015=: ;;
-    *) MSGFMT_015=$MSGFMT ;;
-  esac
-changequote([,])dnl
-  AC_SUBST([MSGFMT_015])
-changequote(,)dnl
   case `$GMSGFMT --version | sed 1q | sed -e 's,^[^0-9]*,,'` in
     '' | 0.[0-9] | 0.[0-9].* | 0.1[0-4] | 0.1[0-4].*) GMSGFMT_015=: ;;
     *) GMSGFMT_015=$GMSGFMT ;;
@@ -83,11 +76,21 @@ changequote([,])dnl
   AM_PATH_PROG_WITH_TEST(MSGMERGE, msgmerge,
     [$ac_dir/$ac_word --update -q /dev/null /dev/null >&]AS_MESSAGE_LOG_FD[ 2>&1], :)
 
-  dnl Installation directories.
-  dnl Autoconf >= 2.60 defines localedir. For older versions of autoconf, we
-  dnl have to define it here, so that it can be used in po/Makefile.
-  test -n "$localedir" || localedir='${datadir}/locale'
-  AC_SUBST([localedir])
+  dnl Test whether it is GNU msgmerge >= 0.20.
+  if LC_ALL=C $MSGMERGE --help | grep ' --for-msgfmt ' >/dev/null; then
+    MSGMERGE_FOR_MSGFMT_OPTION='--for-msgfmt'
+  else
+    dnl Test whether it is GNU msgmerge >= 0.12.
+    if LC_ALL=C $MSGMERGE --help | grep ' --no-fuzzy-matching ' >/dev/null; then
+      MSGMERGE_FOR_MSGFMT_OPTION='--no-fuzzy-matching --no-location --quiet'
+    else
+      dnl With these old versions, $(MSGMERGE) $(MSGMERGE_FOR_MSGFMT_OPTION) is
+      dnl slow. But this is not a big problem, as such old gettext versions are
+      dnl hardly in use any more.
+      MSGMERGE_FOR_MSGFMT_OPTION='--no-location --quiet'
+    fi
+  fi
+  AC_SUBST([MSGMERGE_FOR_MSGFMT_OPTION])
 
   dnl Support for AM_XGETTEXT_OPTION.
   test -n "${XGETTEXT_EXTRA_OPTIONS+set}" || XGETTEXT_EXTRA_OPTIONS=
@@ -130,14 +133,11 @@ changequote([,])dnl
             if test -n "$OBSOLETE_ALL_LINGUAS"; then
               test -n "$as_me" && echo "$as_me: setting ALL_LINGUAS in configure.in is obsolete" || echo "setting ALL_LINGUAS in configure.in is obsolete"
             fi
-            ALL_LINGUAS_=`sed -e "/^#/d" -e "s/#.*//" "$ac_given_srcdir/$ac_dir/LINGUAS"`
-            # Hide the ALL_LINGUAS assignment from automake < 1.5.
-            eval 'ALL_LINGUAS''=$ALL_LINGUAS_'
+            ALL_LINGUAS=`sed -e "/^#/d" -e "s/#.*//" "$ac_given_srcdir/$ac_dir/LINGUAS"`
             POMAKEFILEDEPS="$POMAKEFILEDEPS LINGUAS"
           else
             # The set of available languages was given in configure.in.
-            # Hide the ALL_LINGUAS assignment from automake < 1.5.
-            eval 'ALL_LINGUAS''=$OBSOLETE_ALL_LINGUAS'
+            ALL_LINGUAS=$OBSOLETE_ALL_LINGUAS
           fi
           # Compute POFILES
           # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(lang).po)
@@ -208,9 +208,8 @@ changequote([,])dnl
       esac
     done]],
    [# Capture the value of obsolete ALL_LINGUAS because we need it to compute
-    # POFILES, UPDATEPOFILES, DUMMYPOFILES, GMOFILES, CATALOGS. But hide it
-    # from automake < 1.5.
-    eval 'OBSOLETE_ALL_LINGUAS''="$ALL_LINGUAS"'
+    # POFILES, UPDATEPOFILES, DUMMYPOFILES, GMOFILES, CATALOGS.
+    OBSOLETE_ALL_LINGUAS="$ALL_LINGUAS"
     # Capture the value of LINGUAS because we need it to compute CATALOGS.
     LINGUAS="${LINGUAS-%UNSET%}"
    ])
@@ -311,15 +310,13 @@ changequote([,])dnl
   fi
   if test -f "$ac_given_srcdir/$ac_dir/LINGUAS"; then
     # The LINGUAS file contains the set of available languages.
-    ALL_LINGUAS_=`sed -e "/^#/d" -e "s/#.*//" "$ac_given_srcdir/$ac_dir/LINGUAS"`
+    ALL_LINGUAS=`sed -e "/^#/d" -e "s/#.*//" "$ac_given_srcdir/$ac_dir/LINGUAS"`
     POMAKEFILEDEPS="$POMAKEFILEDEPS LINGUAS"
   else
     # Set ALL_LINGUAS to the value of the Makefile variable LINGUAS.
     sed_x_LINGUAS=`$gt_echo "$sed_x_variable" | sed -e '/^ *#/d' -e 's/VARIABLE/LINGUAS/g'`
-    ALL_LINGUAS_=`sed -n -e "$sed_x_LINGUAS" < "$ac_file"`
+    ALL_LINGUAS=`sed -n -e "$sed_x_LINGUAS" < "$ac_file"`
   fi
-  # Hide the ALL_LINGUAS assignment from automake < 1.5.
-  eval 'ALL_LINGUAS''=$ALL_LINGUAS_'
   # Compute POFILES
   # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(lang).po)
   # Compute UPDATEPOFILES
@@ -329,9 +326,9 @@ changequote([,])dnl
   # Compute GMOFILES
   # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(lang).gmo)
   # Compute PROPERTIESFILES
-  # as      $(foreach lang, $(ALL_LINGUAS), $(top_srcdir)/$(DOMAIN)_$(lang).properties)
+  # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(DOMAIN)_$(lang).properties)
   # Compute CLASSFILES
-  # as      $(foreach lang, $(ALL_LINGUAS), $(top_srcdir)/$(DOMAIN)_$(lang).class)
+  # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(DOMAIN)_$(lang).class)
   # Compute QMFILES
   # as      $(foreach lang, $(ALL_LINGUAS), $(srcdir)/$(lang).qm)
   # Compute MSGFILES
@@ -356,8 +353,8 @@ changequote([,])dnl
     UPDATEPOFILES="$UPDATEPOFILES $lang.po-update"
     DUMMYPOFILES="$DUMMYPOFILES $lang.nop"
     GMOFILES="$GMOFILES $srcdirpre$lang.gmo"
-    PROPERTIESFILES="$PROPERTIESFILES \$(top_srcdir)/\$(DOMAIN)_$lang.properties"
-    CLASSFILES="$CLASSFILES \$(top_srcdir)/\$(DOMAIN)_$lang.class"
+    PROPERTIESFILES="$PROPERTIESFILES \$(srcdir)/\$(DOMAIN)_$lang.properties"
+    CLASSFILES="$CLASSFILES \$(srcdir)/\$(DOMAIN)_$lang.class"
     QMFILES="$QMFILES $srcdirpre$lang.qm"
     frobbedlang=`echo $lang | sed -e 's/\..*$//' -e 'y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/'`
     MSGFILES="$MSGFILES $srcdirpre$frobbedlang.msg"
diff --git a/gl/m4/printf-posix.m4 b/gl/m4/printf-posix.m4
deleted file mode 100644
index d7dfb60f..00000000
--- a/gl/m4/printf-posix.m4
+++ /dev/null
@@ -1,48 +0,0 @@
-# printf-posix.m4 serial 6 (gettext-0.18.2)
-dnl Copyright (C) 2003, 2007, 2009-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-dnl From Bruno Haible.
-dnl Test whether the printf() function supports POSIX/XSI format strings with
-dnl positions.
-
-AC_DEFUN([gt_PRINTF_POSIX],
-[
-  AC_REQUIRE([AC_PROG_CC])
-  AC_CACHE_CHECK([whether printf() supports POSIX/XSI format strings],
-    gt_cv_func_printf_posix,
-    [
-      AC_RUN_IFELSE(
-        [AC_LANG_SOURCE([[
-#include <stdio.h>
-#include <string.h>
-/* The string "%2$d %1$d", with dollar characters protected from the shell's
-   dollar expansion (possibly an autoconf bug).  */
-static char format[] = { '%', '2', '$', 'd', ' ', '%', '1', '$', 'd', '\0' };
-static char buf[100];
-int main ()
-{
-  sprintf (buf, format, 33, 55);
-  return (strcmp (buf, "55 33") != 0);
-}]])],
-        [gt_cv_func_printf_posix=yes],
-        [gt_cv_func_printf_posix=no],
-        [
-          AC_EGREP_CPP([notposix], [
-#if defined __NetBSD__ || defined __BEOS__ || defined _MSC_VER || defined __MINGW32__ || defined __CYGWIN__
-  notposix
-#endif
-            ],
-            [gt_cv_func_printf_posix="guessing no"],
-            [gt_cv_func_printf_posix="guessing yes"])
-        ])
-    ])
-  case $gt_cv_func_printf_posix in
-    *yes)
-      AC_DEFINE([HAVE_POSIX_PRINTF], [1],
-        [Define if your printf() function supports format strings with positions.])
-      ;;
-  esac
-])
diff --git a/gl/m4/printf.m4 b/gl/m4/printf.m4
index ef44f785..4e65abc6 100644
--- a/gl/m4/printf.m4
+++ b/gl/m4/printf.m4
@@ -1,5 +1,5 @@
-# printf.m4 serial 50
-dnl Copyright (C) 2003, 2007-2013 Free Software Foundation, Inc.
+# printf.m4 serial 73
+dnl Copyright (C) 2003, 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -38,6 +38,8 @@ int main ()
   if (sprintf (buf, "%ju %d", (uintmax_t) 12345671, 33, 44, 55) < 0
       || strcmp (buf, "12345671 33") != 0)
     result |= 1;
+#else
+  result |= 1;
 #endif
   buf[0] = '\0';
   if (sprintf (buf, "%zu %d", (size_t) 12345672, 33, 44, 55) < 0
@@ -56,13 +58,16 @@ int main ()
         [gl_cv_func_printf_sizes_c99=yes],
         [gl_cv_func_printf_sizes_c99=no],
         [
-changequote(,)dnl
          case "$host_os" in
+changequote(,)dnl
                                  # Guess yes on glibc systems.
-           *-gnu*)               gl_cv_func_printf_sizes_c99="guessing yes";;
+           *-gnu* | gnu*)        gl_cv_func_printf_sizes_c99="guessing yes";;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_printf_sizes_c99="guessing yes";;
                                  # Guess yes on FreeBSD >= 5.
-           freebsd[1-4]*)        gl_cv_func_printf_sizes_c99="guessing no";;
+           freebsd[1-4].*)       gl_cv_func_printf_sizes_c99="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_printf_sizes_c99="guessing yes";;
+           midnightbsd*)         gl_cv_func_printf_sizes_c99="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_printf_sizes_c99="guessing no";;
            darwin*)              gl_cv_func_printf_sizes_c99="guessing yes";;
@@ -77,10 +82,21 @@ changequote(,)dnl
            netbsd[1-2]* | netbsdelf[1-2]* | netbsdaout[1-2]* | netbsdcoff[1-2]*)
                                  gl_cv_func_printf_sizes_c99="guessing no";;
            netbsd*)              gl_cv_func_printf_sizes_c99="guessing yes";;
-                                 # If we don't know, assume the worst.
-           *)                    gl_cv_func_printf_sizes_c99="guessing no";;
-         esac
+                                 # Guess yes on Android.
+           linux*-android*)      gl_cv_func_printf_sizes_c99="guessing yes";;
 changequote([,])dnl
+                                 # Guess yes on MSVC, no on mingw.
+           mingw*)               AC_EGREP_CPP([Known], [
+#ifdef _MSC_VER
+ Known
+#endif
+                                   ],
+                                   [gl_cv_func_printf_sizes_c99="guessing yes"],
+                                   [gl_cv_func_printf_sizes_c99="guessing no"])
+                                 ;;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_printf_sizes_c99="$gl_cross_guess_normal";;
+         esac
         ])
     ])
 ])
@@ -120,14 +136,22 @@ int main ()
 }]])],
         [gl_cv_func_printf_long_double=yes],
         [gl_cv_func_printf_long_double=no],
-        [
-changequote(,)dnl
-         case "$host_os" in
-           beos*)        gl_cv_func_printf_long_double="guessing no";;
-           mingw* | pw*) gl_cv_func_printf_long_double="guessing no";;
-           *)            gl_cv_func_printf_long_double="guessing yes";;
+        [case "$host_os" in
+                            # Guess no on BeOS.
+           beos*)           gl_cv_func_printf_long_double="guessing no";;
+                            # Guess yes on Android.
+           linux*-android*) gl_cv_func_printf_long_double="guessing yes";;
+                            # Guess yes on MSVC, no on mingw.
+           mingw*)          AC_EGREP_CPP([Known], [
+#ifdef _MSC_VER
+ Known
+#endif
+                              ],
+                              [gl_cv_func_printf_long_double="guessing yes"],
+                              [gl_cv_func_printf_long_double="guessing no"])
+                            ;;
+           *)               gl_cv_func_printf_long_double="guessing yes";;
          esac
-changequote([,])dnl
         ])
     ])
 ])
@@ -215,13 +239,16 @@ int main ()
         [gl_cv_func_printf_infinite=yes],
         [gl_cv_func_printf_infinite=no],
         [
-changequote(,)dnl
          case "$host_os" in
+changequote(,)dnl
                                  # Guess yes on glibc systems.
-           *-gnu*)               gl_cv_func_printf_infinite="guessing yes";;
+           *-gnu* | gnu*)        gl_cv_func_printf_infinite="guessing yes";;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_printf_infinite="guessing yes";;
                                  # Guess yes on FreeBSD >= 6.
-           freebsd[1-5]*)        gl_cv_func_printf_infinite="guessing no";;
+           freebsd[1-5].*)       gl_cv_func_printf_infinite="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_printf_infinite="guessing yes";;
+           midnightbsd*)         gl_cv_func_printf_infinite="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_printf_infinite="guessing no";;
            darwin*)              gl_cv_func_printf_infinite="guessing yes";;
@@ -232,12 +259,26 @@ changequote(,)dnl
            netbsd[1-2]* | netbsdelf[1-2]* | netbsdaout[1-2]* | netbsdcoff[1-2]*)
                                  gl_cv_func_printf_infinite="guessing no";;
            netbsd*)              gl_cv_func_printf_infinite="guessing yes";;
+                                 # Guess yes on OpenBSD >= 6.0.
+           openbsd[1-5].*)       gl_cv_func_printf_infinite="guessing no";;
+           openbsd*)             gl_cv_func_printf_infinite="guessing yes";;
                                  # Guess yes on BeOS.
            beos*)                gl_cv_func_printf_infinite="guessing yes";;
-                                 # If we don't know, assume the worst.
-           *)                    gl_cv_func_printf_infinite="guessing no";;
-         esac
+                                 # Guess no on Android.
+           linux*-android*)      gl_cv_func_printf_infinite="guessing no";;
 changequote([,])dnl
+                                 # Guess yes on MSVC, no on mingw.
+           mingw*)               AC_EGREP_CPP([Known], [
+#ifdef _MSC_VER
+ Known
+#endif
+                                   ],
+                                   [gl_cv_func_printf_infinite="guessing yes"],
+                                   [gl_cv_func_printf_infinite="guessing no"])
+                                 ;;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_printf_infinite="$gl_cross_guess_normal";;
+         esac
         ])
     ])
 ])
@@ -328,7 +369,7 @@ int main ()
 # ifdef WORDS_BIGENDIAN
 #  define LDBL80_WORDS(exponent,manthi,mantlo) \
      { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \
-       ((unsigned int) (manthi) << 16) | (unsigned int) (mantlo) >> 16),    \
+       ((unsigned int) (manthi) << 16) | ((unsigned int) (mantlo) >> 16),   \
        (unsigned int) (mantlo) << 16                                        \
      }
 # else
@@ -365,66 +406,51 @@ int main ()
   { /* Pseudo-NaN.  */
     static union { unsigned int word[4]; long double value; } x =
       { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) };
-    if (sprintf (buf, "%Lf", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Lf", x.value) <= 0)
       result |= 4;
-    if (sprintf (buf, "%Le", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Le", x.value) <= 0)
       result |= 4;
-    if (sprintf (buf, "%Lg", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Lg", x.value) <= 0)
       result |= 4;
   }
   { /* Pseudo-Infinity.  */
     static union { unsigned int word[4]; long double value; } x =
       { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) };
-    if (sprintf (buf, "%Lf", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Lf", x.value) <= 0)
       result |= 8;
-    if (sprintf (buf, "%Le", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Le", x.value) <= 0)
       result |= 8;
-    if (sprintf (buf, "%Lg", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Lg", x.value) <= 0)
       result |= 8;
   }
   { /* Pseudo-Zero.  */
     static union { unsigned int word[4]; long double value; } x =
       { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) };
-    if (sprintf (buf, "%Lf", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Lf", x.value) <= 0)
       result |= 16;
-    if (sprintf (buf, "%Le", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Le", x.value) <= 0)
       result |= 16;
-    if (sprintf (buf, "%Lg", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Lg", x.value) <= 0)
       result |= 16;
   }
   { /* Unnormalized number.  */
     static union { unsigned int word[4]; long double value; } x =
       { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) };
-    if (sprintf (buf, "%Lf", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Lf", x.value) <= 0)
       result |= 32;
-    if (sprintf (buf, "%Le", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Le", x.value) <= 0)
       result |= 32;
-    if (sprintf (buf, "%Lg", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Lg", x.value) <= 0)
       result |= 32;
   }
   { /* Pseudo-Denormal.  */
     static union { unsigned int word[4]; long double value; } x =
       { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) };
-    if (sprintf (buf, "%Lf", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Lf", x.value) <= 0)
       result |= 64;
-    if (sprintf (buf, "%Le", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Le", x.value) <= 0)
       result |= 64;
-    if (sprintf (buf, "%Lg", x.value) < 0
-        || !strisnan (buf, 0, strlen (buf)))
+    if (sprintf (buf, "%Lg", x.value) <= 0)
       result |= 64;
   }
 #endif
@@ -432,27 +458,43 @@ int main ()
 }]])],
             [gl_cv_func_printf_infinite_long_double=yes],
             [gl_cv_func_printf_infinite_long_double=no],
-            [
-changequote(,)dnl
-             case "$host_cpu" in
+            [case "$host_cpu" in
                                      # Guess no on ia64, x86_64, i386.
                ia64 | x86_64 | i*86) gl_cv_func_printf_infinite_long_double="guessing no";;
                *)
                  case "$host_os" in
+changequote(,)dnl
                                          # Guess yes on glibc systems.
-                   *-gnu*)               gl_cv_func_printf_infinite_long_double="guessing yes";;
+                   *-gnu* | gnu*)        gl_cv_func_printf_infinite_long_double="guessing yes";;
+                                         # Guess yes on musl systems.
+                   *-musl*)              gl_cv_func_printf_infinite_long_double="guessing yes";;
                                          # Guess yes on FreeBSD >= 6.
-                   freebsd[1-5]*)        gl_cv_func_printf_infinite_long_double="guessing no";;
+                   freebsd[1-5].*)       gl_cv_func_printf_infinite_long_double="guessing no";;
                    freebsd* | kfreebsd*) gl_cv_func_printf_infinite_long_double="guessing yes";;
+                   midnightbsd*)         gl_cv_func_printf_infinite_long_double="guessing yes";;
                                          # Guess yes on HP-UX >= 11.
                    hpux[7-9]* | hpux10*) gl_cv_func_printf_infinite_long_double="guessing no";;
                    hpux*)                gl_cv_func_printf_infinite_long_double="guessing yes";;
-                                         # If we don't know, assume the worst.
-                   *)                    gl_cv_func_printf_infinite_long_double="guessing no";;
+                                         # Guess yes on OpenBSD >= 6.0.
+                   openbsd[1-5].*)       gl_cv_func_printf_infinite_long_double="guessing no";;
+                   openbsd*)             gl_cv_func_printf_infinite_long_double="guessing yes";;
+                                         # Guess no on Android.
+                   linux*-android*)      gl_cv_func_printf_infinite_long_double="guessing no";;
+changequote([,])dnl
+                                         # Guess yes on MSVC, no on mingw.
+                   mingw*)               AC_EGREP_CPP([Known], [
+#ifdef _MSC_VER
+ Known
+#endif
+                                           ],
+                                           [gl_cv_func_printf_infinite_long_double="guessing yes"],
+                                           [gl_cv_func_printf_infinite_long_double="guessing no"])
+                                         ;;
+                                         # If we don't know, obey --enable-cross-guesses.
+                   *)                    gl_cv_func_printf_infinite_long_double="$gl_cross_guess_normal";;
                  esac
                  ;;
              esac
-changequote([,])dnl
             ])
         ])
       ;;
@@ -495,15 +537,22 @@ int main ()
           && strcmp (buf, "-0X6.488P-1 33") != 0
           && strcmp (buf, "-0XC.91P-2 33") != 0))
     result |= 2;
-  /* This catches a FreeBSD 6.1 bug: it doesn't round.  */
+  /* This catches a FreeBSD 13.0 bug: it doesn't round.  */
   if (sprintf (buf, "%.2a %d", 1.51, 33, 44, 55) < 0
       || (strcmp (buf, "0x1.83p+0 33") != 0
           && strcmp (buf, "0x3.05p-1 33") != 0
           && strcmp (buf, "0x6.0ap-2 33") != 0
           && strcmp (buf, "0xc.14p-3 33") != 0))
     result |= 4;
+  /* This catches a Mac OS X 10.12.4 (Darwin 16.5) bug: it doesn't round.  */
+  if (sprintf (buf, "%.0a %d", 1.51, 33, 44, 55) < 0
+      || (strcmp (buf, "0x2p+0 33") != 0
+          && strcmp (buf, "0x3p-1 33") != 0
+          && strcmp (buf, "0x6p-2 33") != 0
+          && strcmp (buf, "0xcp-3 33") != 0))
+    result |= 4;
   /* This catches a FreeBSD 6.1 bug.  See
-     <http://lists.gnu.org/archive/html/bug-gnulib/2007-04/msg00107.html> */
+     <https://lists.gnu.org/r/bug-gnulib/2007-04/msg00107.html> */
   if (sprintf (buf, "%010a %d", 1.0 / zero, 33, 44, 55) < 0
       || buf[0] == '0')
     result |= 8;
@@ -515,7 +564,7 @@ int main ()
           && strcmp (buf, "0x8.0p-2") != 0))
     result |= 16;
   /* This catches the same Mac OS X 10.3.9 (Darwin 7.9) bug and also a
-     glibc 2.4 bug <http://sourceware.org/bugzilla/show_bug.cgi?id=2908>.  */
+     glibc 2.4 bug <https://sourceware.org/bugzilla/show_bug.cgi?id=2908>.  */
   if (sprintf (buf, "%.1La", 1.999L) < 0
       || (strcmp (buf, "0x1.0p+1") != 0
           && strcmp (buf, "0x2.0p+0") != 0
@@ -529,7 +578,7 @@ int main ()
         [
          case "$host_os" in
                                  # Guess yes on glibc >= 2.5 systems.
-           *-gnu*)
+           *-gnu* | gnu*)
              AC_EGREP_CPP([BZ2908], [
                #include <features.h>
                #ifdef __GNU_LIBRARY__
@@ -541,8 +590,14 @@ int main ()
                [gl_cv_func_printf_directive_a="guessing yes"],
                [gl_cv_func_printf_directive_a="guessing no"])
              ;;
-                                 # If we don't know, assume the worst.
-           *)                    gl_cv_func_printf_directive_a="guessing no";;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_printf_directive_a="guessing yes";;
+                                 # Guess no on Android.
+           linux*-android*)      gl_cv_func_printf_directive_a="guessing no";;
+                                 # Guess no on native Windows.
+           mingw*)               gl_cv_func_printf_directive_a="guessing no";;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_printf_directive_a="$gl_cross_guess_normal";;
          esac
         ])
     ])
@@ -583,23 +638,40 @@ int main ()
         [gl_cv_func_printf_directive_f=yes],
         [gl_cv_func_printf_directive_f=no],
         [
-changequote(,)dnl
          case "$host_os" in
+changequote(,)dnl
                                  # Guess yes on glibc systems.
-           *-gnu*)               gl_cv_func_printf_directive_f="guessing yes";;
+           *-gnu* | gnu*)        gl_cv_func_printf_directive_f="guessing yes";;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_printf_directive_f="guessing yes";;
                                  # Guess yes on FreeBSD >= 6.
-           freebsd[1-5]*)        gl_cv_func_printf_directive_f="guessing no";;
+           freebsd[1-5].*)       gl_cv_func_printf_directive_f="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_printf_directive_f="guessing yes";;
+           midnightbsd*)         gl_cv_func_printf_directive_f="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_printf_directive_f="guessing no";;
            darwin*)              gl_cv_func_printf_directive_f="guessing yes";;
+                                 # Guess yes on OpenBSD >= 6.0.
+           openbsd[1-5].*)       gl_cv_func_printf_directive_f="guessing no";;
+           openbsd*)             gl_cv_func_printf_directive_f="guessing yes";;
                                  # Guess yes on Solaris >= 2.10.
-           solaris2.[1-9][0-9]*) gl_cv_func_printf_sizes_c99="guessing yes";;
-           solaris*)             gl_cv_func_printf_sizes_c99="guessing no";;
-                                 # If we don't know, assume the worst.
-           *)                    gl_cv_func_printf_directive_f="guessing no";;
-         esac
+           solaris2.[1-9][0-9]*) gl_cv_func_printf_directive_f="guessing yes";;
+           solaris*)             gl_cv_func_printf_directive_f="guessing no";;
+                                 # Guess no on Android.
+           linux*-android*)      gl_cv_func_printf_directive_f="guessing no";;
 changequote([,])dnl
+                                 # Guess yes on MSVC, no on mingw.
+           mingw*)               AC_EGREP_CPP([Known], [
+#ifdef _MSC_VER
+ Known
+#endif
+                                   ],
+                                   [gl_cv_func_printf_directive_f="guessing yes"],
+                                   [gl_cv_func_printf_directive_f="guessing no"])
+                                 ;;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_printf_directive_f="$gl_cross_guess_normal";;
+         esac
         ])
     ])
 ])
@@ -621,7 +693,10 @@ AC_DEFUN([gl_PRINTF_DIRECTIVE_N],
 #include <stdlib.h>
 #include <string.h>
 #ifdef _MSC_VER
-/* See page about "Parameter Validation" on msdn.microsoft.com.  */
+#include <inttypes.h>
+/* See page about "Parameter Validation" on msdn.microsoft.com.
+   <https://docs.microsoft.com/en-us/cpp/c-runtime-library/parameter-validation>
+   <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/set-invalid-parameter-handler-set-thread-local-invalid-parameter-handler>  */
 static void cdecl
 invalid_parameter_handler (const wchar_t *expression,
                            const wchar_t *function,
@@ -651,13 +726,23 @@ int main ()
 }]])],
         [gl_cv_func_printf_directive_n=yes],
         [gl_cv_func_printf_directive_n=no],
-        [
-changequote(,)dnl
-         case "$host_os" in
-           mingw*) gl_cv_func_printf_directive_n="guessing no";;
-           *)      gl_cv_func_printf_directive_n="guessing yes";;
+        [case "$host_os" in
+                            # Guess no on glibc when _FORTIFY_SOURCE >= 2.
+           *-gnu* | gnu*)   AC_COMPILE_IFELSE(
+                              [AC_LANG_SOURCE(
+                                 [[#if _FORTIFY_SOURCE >= 2
+                                    error fail
+                                   #endif
+                                 ]])],
+                              [gl_cv_func_printf_directive_n="guessing yes"],
+                              [gl_cv_func_printf_directive_n="guessing no"])
+                            ;;
+                            # Guess no on Android.
+           linux*-android*) gl_cv_func_printf_directive_n="guessing no";;
+                            # Guess no on native Windows.
+           mingw*)          gl_cv_func_printf_directive_n="guessing no";;
+           *)               gl_cv_func_printf_directive_n="guessing yes";;
          esac
-changequote([,])dnl
         ])
     ])
 ])
@@ -678,13 +763,7 @@ AC_DEFUN([gl_PRINTF_DIRECTIVE_LS],
     [
       AC_RUN_IFELSE(
         [AC_LANG_SOURCE([[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
 #include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 #include <string.h>
 int main ()
@@ -732,11 +811,17 @@ int main ()
         [
 changequote(,)dnl
          case "$host_os" in
-           openbsd*)        gl_cv_func_printf_directive_ls="guessing no";;
+                            # Guess yes on OpenBSD >= 6.0.
+           openbsd[1-5].*)  gl_cv_func_printf_directive_ls="guessing no";;
+           openbsd*)        gl_cv_func_printf_directive_ls="guessing yes";;
            irix*)           gl_cv_func_printf_directive_ls="guessing no";;
            solaris*)        gl_cv_func_printf_directive_ls="guessing no";;
            cygwin*)         gl_cv_func_printf_directive_ls="guessing no";;
            beos* | haiku*)  gl_cv_func_printf_directive_ls="guessing no";;
+                            # Guess no on Android.
+           linux*-android*) gl_cv_func_printf_directive_ls="guessing no";;
+                            # Guess yes on native Windows.
+           mingw*)          gl_cv_func_printf_directive_ls="guessing yes";;
            *)               gl_cv_func_printf_directive_ls="guessing yes";;
          esac
 changequote([,])dnl
@@ -774,10 +859,13 @@ int main ()
 changequote(,)dnl
          case "$host_os" in
            netbsd[1-3]* | netbsdelf[1-3]* | netbsdaout[1-3]* | netbsdcoff[1-3]*)
-                         gl_cv_func_printf_positions="guessing no";;
-           beos*)        gl_cv_func_printf_positions="guessing no";;
-           mingw* | pw*) gl_cv_func_printf_positions="guessing no";;
-           *)            gl_cv_func_printf_positions="guessing yes";;
+                            gl_cv_func_printf_positions="guessing no";;
+           beos*)           gl_cv_func_printf_positions="guessing no";;
+                            # Guess yes on Android.
+           linux*-android*) gl_cv_func_printf_positions="guessing yes";;
+                            # Guess no on native Windows.
+           mingw* | pw*)    gl_cv_func_printf_positions="guessing no";;
+           *)               gl_cv_func_printf_positions="guessing yes";;
          esac
 changequote([,])dnl
         ])
@@ -812,10 +900,13 @@ int main ()
         [
 changequote(,)dnl
          case "$host_os" in
-           cygwin*)      gl_cv_func_printf_flag_grouping="guessing no";;
-           netbsd*)      gl_cv_func_printf_flag_grouping="guessing no";;
-           mingw* | pw*) gl_cv_func_printf_flag_grouping="guessing no";;
-           *)            gl_cv_func_printf_flag_grouping="guessing yes";;
+           cygwin*)         gl_cv_func_printf_flag_grouping="guessing no";;
+           netbsd*)         gl_cv_func_printf_flag_grouping="guessing no";;
+                            # Guess no on Android.
+           linux*-android*) gl_cv_func_printf_flag_grouping="guessing no";;
+                            # Guess no on native Windows.
+           mingw* | pw*)    gl_cv_func_printf_flag_grouping="guessing no";;
+           *)               gl_cv_func_printf_flag_grouping="guessing yes";;
          esac
 changequote([,])dnl
         ])
@@ -824,7 +915,7 @@ changequote([,])dnl
 
 dnl Test whether the *printf family of functions supports the - flag correctly.
 dnl (ISO C99.) See
-dnl <http://lists.gnu.org/archive/html/bug-coreutils/2008-02/msg00035.html>
+dnl <https://lists.gnu.org/r/bug-coreutils/2008-02/msg00035.html>
 dnl Result is gl_cv_func_printf_flag_leftadjust.
 
 AC_DEFUN([gl_PRINTF_FLAG_LEFTADJUST],
@@ -852,12 +943,16 @@ int main ()
         [
 changequote(,)dnl
          case "$host_os" in
-                    # Guess yes on HP-UX 11.
-           hpux11*) gl_cv_func_printf_flag_leftadjust="guessing yes";;
-                    # Guess no on HP-UX 10 and older.
-           hpux*)   gl_cv_func_printf_flag_leftadjust="guessing no";;
-                    # Guess yes otherwise.
-           *)       gl_cv_func_printf_flag_leftadjust="guessing yes";;
+                            # Guess yes on HP-UX 11.
+           hpux11*)         gl_cv_func_printf_flag_leftadjust="guessing yes";;
+                            # Guess no on HP-UX 10 and older.
+           hpux*)           gl_cv_func_printf_flag_leftadjust="guessing no";;
+                            # Guess yes on Android.
+           linux*-android*) gl_cv_func_printf_flag_leftadjust="guessing yes";;
+                            # Guess yes on native Windows.
+           mingw*)          gl_cv_func_printf_flag_leftadjust="guessing yes";;
+                            # Guess yes otherwise.
+           *)               gl_cv_func_printf_flag_leftadjust="guessing yes";;
          esac
 changequote([,])dnl
         ])
@@ -866,7 +961,7 @@ changequote([,])dnl
 
 dnl Test whether the *printf family of functions supports padding of non-finite
 dnl values with the 0 flag correctly. (ISO C99 + TC1 + TC2.) See
-dnl <http://lists.gnu.org/archive/html/bug-gnulib/2007-04/msg00107.html>
+dnl <https://lists.gnu.org/r/bug-gnulib/2007-04/msg00107.html>
 dnl Result is gl_cv_func_printf_flag_zero.
 
 AC_DEFUN([gl_PRINTF_FLAG_ZERO],
@@ -895,12 +990,18 @@ int main ()
         [
 changequote(,)dnl
          case "$host_os" in
-                   # Guess yes on glibc systems.
-           *-gnu*) gl_cv_func_printf_flag_zero="guessing yes";;
-                   # Guess yes on BeOS.
-           beos*)  gl_cv_func_printf_flag_zero="guessing yes";;
-                   # If we don't know, assume the worst.
-           *)      gl_cv_func_printf_flag_zero="guessing no";;
+                            # Guess yes on glibc systems.
+           *-gnu* | gnu*)   gl_cv_func_printf_flag_zero="guessing yes";;
+                            # Guess yes on musl systems.
+           *-musl*)         gl_cv_func_printf_flag_zero="guessing yes";;
+                            # Guess yes on BeOS.
+           beos*)           gl_cv_func_printf_flag_zero="guessing yes";;
+                            # Guess no on Android.
+           linux*-android*) gl_cv_func_printf_flag_zero="guessing no";;
+                            # Guess no on native Windows.
+           mingw*)          gl_cv_func_printf_flag_zero="guessing no";;
+                            # If we don't know, obey --enable-cross-guesses.
+           *)               gl_cv_func_printf_flag_zero="$gl_cross_guess_normal";;
          esac
 changequote([,])dnl
         ])
@@ -953,10 +1054,12 @@ int main ()
 changequote(,)dnl
          case "$host_os" in
            # Guess no only on Solaris, native Windows, and BeOS systems.
-           solaris*)     gl_cv_func_printf_precision="guessing no" ;;
-           mingw* | pw*) gl_cv_func_printf_precision="guessing no" ;;
-           beos*)        gl_cv_func_printf_precision="guessing no" ;;
-           *)            gl_cv_func_printf_precision="guessing yes" ;;
+           solaris*)        gl_cv_func_printf_precision="guessing no" ;;
+           mingw* | pw*)    gl_cv_func_printf_precision="guessing no" ;;
+           beos*)           gl_cv_func_printf_precision="guessing no" ;;
+                            # Guess yes on Android.
+           linux*-android*) gl_cv_func_printf_precision="guessing yes" ;;
+           *)               gl_cv_func_printf_precision="guessing yes" ;;
          esac
 changequote([,])dnl
         ])
@@ -978,9 +1081,8 @@ AC_DEFUN([gl_PRINTF_ENOMEM],
       gl_cv_func_printf_enomem="guessing no"
       if test "$cross_compiling" = no; then
         if test $APPLE_UNIVERSAL_BUILD = 0; then
-          AC_LANG_CONFTEST([AC_LANG_SOURCE([
+          AC_LANG_CONFTEST([AC_LANG_SOURCE([[
 ]GL_NOCRASH[
-changequote(,)dnl
 #include <stdio.h>
 #include <sys/types.h>
 #include <sys/time.h>
@@ -1025,8 +1127,7 @@ int main()
   ret = printf ("%.5000000f", 1.0);
   return !(ret == 5000002 || (ret < 0 && errno == ENOMEM));
 }
-changequote([,])dnl
-          ])])
+          ]])])
           if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
             (./conftest 2>&AS_MESSAGE_LOG_FD
              result=$?
@@ -1053,28 +1154,30 @@ changequote([,])dnl
       if test "$gl_cv_func_printf_enomem" = "guessing no"; then
 changequote(,)dnl
         case "$host_os" in
-                    # Guess yes on glibc systems.
-          *-gnu*)   gl_cv_func_printf_enomem="guessing yes";;
-                    # Guess yes on Solaris.
-          solaris*) gl_cv_func_printf_enomem="guessing yes";;
-                    # Guess yes on AIX.
-          aix*)     gl_cv_func_printf_enomem="guessing yes";;
-                    # Guess yes on HP-UX/hppa.
-          hpux*)    case "$host_cpu" in
-                      hppa*) gl_cv_func_printf_enomem="guessing yes";;
-                      *)     gl_cv_func_printf_enomem="guessing no";;
-                    esac
-                    ;;
-                    # Guess yes on IRIX.
-          irix*)    gl_cv_func_printf_enomem="guessing yes";;
-                    # Guess yes on OSF/1.
-          osf*)     gl_cv_func_printf_enomem="guessing yes";;
-                    # Guess yes on BeOS.
-          beos*)    gl_cv_func_printf_enomem="guessing yes";;
-                    # Guess yes on Haiku.
-          haiku*)   gl_cv_func_printf_enomem="guessing yes";;
-                    # If we don't know, assume the worst.
-          *)        gl_cv_func_printf_enomem="guessing no";;
+                           # Guess yes on glibc systems.
+          *-gnu* | gnu*)   gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess yes on Solaris.
+          solaris*)        gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess yes on AIX.
+          aix*)            gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess yes on HP-UX/hppa.
+          hpux*)           case "$host_cpu" in
+                             hppa*) gl_cv_func_printf_enomem="guessing yes";;
+                             *)     gl_cv_func_printf_enomem="guessing no";;
+                           esac
+                           ;;
+                           # Guess yes on IRIX.
+          irix*)           gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess yes on OSF/1.
+          osf*)            gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess yes on BeOS.
+          beos*)           gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess yes on Haiku.
+          haiku*)          gl_cv_func_printf_enomem="guessing yes";;
+                           # Guess no on Android.
+          linux*-android*) gl_cv_func_printf_enomem="guessing no";;
+                           # If we don't know, obey --enable-cross-guesses.
+          *)               gl_cv_func_printf_enomem="$gl_cross_guess_normal";;
         esac
 changequote([,])dnl
       fi
@@ -1093,7 +1196,7 @@ dnl Test whether the string produced by the snprintf function is always NUL
 dnl terminated. (ISO C99, POSIX:2001)
 dnl Result is gl_cv_func_snprintf_truncation_c99.
 
-AC_DEFUN([gl_SNPRINTF_TRUNCATION_C99],
+AC_DEFUN_ONCE([gl_SNPRINTF_TRUNCATION_C99],
 [
   AC_REQUIRE([AC_PROG_CC])
   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
@@ -1134,10 +1237,13 @@ int main ()
 changequote(,)dnl
          case "$host_os" in
                                  # Guess yes on glibc systems.
-           *-gnu*)               gl_cv_func_snprintf_truncation_c99="guessing yes";;
+           *-gnu* | gnu*)        gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_snprintf_truncation_c99="guessing yes";;
                                  # Guess yes on FreeBSD >= 5.
-           freebsd[1-4]*)        gl_cv_func_snprintf_truncation_c99="guessing no";;
+           freebsd[1-4].*)       gl_cv_func_snprintf_truncation_c99="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_snprintf_truncation_c99="guessing yes";;
+           midnightbsd*)         gl_cv_func_snprintf_truncation_c99="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_snprintf_truncation_c99="guessing no";;
            darwin*)              gl_cv_func_snprintf_truncation_c99="guessing yes";;
@@ -1166,8 +1272,12 @@ changequote(,)dnl
            netbsd*)              gl_cv_func_snprintf_truncation_c99="guessing yes";;
                                  # Guess yes on BeOS.
            beos*)                gl_cv_func_snprintf_truncation_c99="guessing yes";;
-                                 # If we don't know, assume the worst.
-           *)                    gl_cv_func_snprintf_truncation_c99="guessing no";;
+                                 # Guess yes on Android.
+           linux*-android*)      gl_cv_func_snprintf_truncation_c99="guessing yes";;
+                                 # Guess no on native Windows.
+           mingw*)               gl_cv_func_snprintf_truncation_c99="guessing no";;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_snprintf_truncation_c99="$gl_cross_guess_normal";;
          esac
 changequote([,])dnl
         ])
@@ -1229,14 +1339,16 @@ int main ()
 }]])],
         [gl_cv_func_snprintf_retval_c99=yes],
         [gl_cv_func_snprintf_retval_c99=no],
-        [
+        [case "$host_os" in
 changequote(,)dnl
-         case "$host_os" in
                                  # Guess yes on glibc systems.
-           *-gnu*)               gl_cv_func_snprintf_retval_c99="guessing yes";;
+           *-gnu* | gnu*)        gl_cv_func_snprintf_retval_c99="guessing yes";;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_snprintf_retval_c99="guessing yes";;
                                  # Guess yes on FreeBSD >= 5.
-           freebsd[1-4]*)        gl_cv_func_snprintf_retval_c99="guessing no";;
+           freebsd[1-4].*)       gl_cv_func_snprintf_retval_c99="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_snprintf_retval_c99="guessing yes";;
+           midnightbsd*)         gl_cv_func_snprintf_retval_c99="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_snprintf_retval_c99="guessing no";;
            darwin*)              gl_cv_func_snprintf_retval_c99="guessing yes";;
@@ -1256,10 +1368,21 @@ changequote(,)dnl
            netbsd*)              gl_cv_func_snprintf_retval_c99="guessing yes";;
                                  # Guess yes on BeOS.
            beos*)                gl_cv_func_snprintf_retval_c99="guessing yes";;
-                                 # If we don't know, assume the worst.
-           *)                    gl_cv_func_snprintf_retval_c99="guessing no";;
-         esac
+                                 # Guess yes on Android.
+           linux*-android*)      gl_cv_func_snprintf_retval_c99="guessing yes";;
 changequote([,])dnl
+                                 # Guess yes on MSVC, no on mingw.
+           mingw*)               AC_EGREP_CPP([Known], [
+#ifdef _MSC_VER
+ Known
+#endif
+                                   ],
+                                   [gl_cv_func_snprintf_retval_c99="guessing yes"],
+                                   [gl_cv_func_snprintf_retval_c99="guessing no"])
+                                 ;;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_snprintf_retval_c99="$gl_cross_guess_normal";;
+         esac
         ])
     ])
 ])
@@ -1311,13 +1434,24 @@ int main ()
         [gl_cv_func_snprintf_directive_n=yes],
         [gl_cv_func_snprintf_directive_n=no],
         [
-changequote(,)dnl
          case "$host_os" in
-                                 # Guess yes on glibc systems.
-           *-gnu*)               gl_cv_func_snprintf_directive_n="guessing yes";;
+                                 # Guess no on glibc when _FORTIFY_SOURCE >= 2.
+           *-gnu* | gnu*)        AC_COMPILE_IFELSE(
+                                   [AC_LANG_SOURCE(
+                                      [[#if _FORTIFY_SOURCE >= 2
+                                         error fail
+                                        #endif
+                                      ]])],
+                                   [gl_cv_func_snprintf_directive_n="guessing yes"],
+                                   [gl_cv_func_snprintf_directive_n="guessing no"])
+                                 ;;
+changequote(,)dnl
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_snprintf_directive_n="guessing yes";;
                                  # Guess yes on FreeBSD >= 5.
-           freebsd[1-4]*)        gl_cv_func_snprintf_directive_n="guessing no";;
+           freebsd[1-4].*)       gl_cv_func_snprintf_directive_n="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_snprintf_directive_n="guessing yes";;
+           midnightbsd*)         gl_cv_func_snprintf_directive_n="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_snprintf_directive_n="guessing no";;
            darwin*)              gl_cv_func_snprintf_directive_n="guessing yes";;
@@ -1339,10 +1473,14 @@ changequote(,)dnl
            netbsd*)              gl_cv_func_snprintf_directive_n="guessing yes";;
                                  # Guess yes on BeOS.
            beos*)                gl_cv_func_snprintf_directive_n="guessing yes";;
-                                 # If we don't know, assume the worst.
-           *)                    gl_cv_func_snprintf_directive_n="guessing no";;
-         esac
+                                 # Guess no on Android.
+           linux*-android*)      gl_cv_func_snprintf_directive_n="guessing no";;
+                                 # Guess no on native Windows.
+           mingw*)               gl_cv_func_snprintf_directive_n="guessing no";;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_snprintf_directive_n="$gl_cross_guess_normal";;
 changequote([,])dnl
+         esac
         ])
     ])
 ])
@@ -1355,6 +1493,7 @@ dnl Result is gl_cv_func_snprintf_size1.
 AC_DEFUN([gl_SNPRINTF_SIZE1],
 [
   AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
   AC_REQUIRE([gl_SNPRINTF_PRESENCE])
   AC_CACHE_CHECK([whether snprintf respects a size of 1],
     [gl_cv_func_snprintf_size1],
@@ -1384,7 +1523,14 @@ int main()
 }]])],
         [gl_cv_func_snprintf_size1=yes],
         [gl_cv_func_snprintf_size1=no],
-        [gl_cv_func_snprintf_size1="guessing yes"])
+        [case "$host_os" in
+                            # Guess yes on Android.
+           linux*-android*) gl_cv_func_snprintf_size1="guessing yes" ;;
+                            # Guess yes on native Windows.
+           mingw*)          gl_cv_func_snprintf_size1="guessing yes" ;;
+           *)               gl_cv_func_snprintf_size1="guessing yes" ;;
+         esac
+        ])
     ])
 ])
 
@@ -1456,10 +1602,13 @@ int main()
 changequote(,)dnl
          case "$host_os" in
                                  # Guess yes on glibc systems.
-           *-gnu*)               gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+           *-gnu* | gnu*)        gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # Guess yes on musl systems.
+           *-musl*)              gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
                                  # Guess yes on FreeBSD >= 5.
-           freebsd[1-4]*)        gl_cv_func_vsnprintf_zerosize_c99="guessing no";;
+           freebsd[1-4].*)       gl_cv_func_vsnprintf_zerosize_c99="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+           midnightbsd*)         gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_vsnprintf_zerosize_c99="guessing no";;
            darwin*)              gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
@@ -1480,10 +1629,12 @@ changequote(,)dnl
            netbsd*)              gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
                                  # Guess yes on BeOS.
            beos*)                gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
-                                 # Guess yes on mingw.
+                                 # Guess yes on Android.
+           linux*-android*)      gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+                                 # Guess yes on native Windows.
            mingw* | pw*)         gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
-                                 # If we don't know, assume the worst.
-           *)                    gl_cv_func_vsnprintf_zerosize_c99="guessing no";;
+                                 # If we don't know, obey --enable-cross-guesses.
+           *)                    gl_cv_func_vsnprintf_zerosize_c99="$gl_cross_guess_normal";;
          esac
 changequote([,])dnl
         ])
@@ -1539,14 +1690,19 @@ dnl
 dnl                                  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20
 dnl   glibc 2.5                      .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .
 dnl   glibc 2.3.6                    .  .  .  .  #  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .
+dnl   FreeBSD 13.0                   .  .  .  .  #  .  .  .  .  .  .  .  .  #  .  .  .  .  .  .
 dnl   FreeBSD 5.4, 6.1               .  .  .  .  #  .  .  .  .  .  .  #  .  #  .  .  .  .  .  .
+dnl   Mac OS X 10.13.5               .  .  .  #  #  .  #  .  .  .  .  .  .  .  .  .  .  #  .  .
 dnl   Mac OS X 10.5.8                .  .  .  #  #  .  .  .  .  .  .  #  .  .  .  .  .  .  .  .
 dnl   Mac OS X 10.3.9                .  .  .  .  #  .  .  .  .  .  .  #  .  #  .  .  .  .  .  .
+dnl   OpenBSD 6.0, 6.7               .  .  .  .  #  .  .  .  .  .  .  .  .  #  .  .  .  .  .  .
 dnl   OpenBSD 3.9, 4.0               .  .  #  #  #  #  .  #  .  #  .  #  .  #  .  .  .  .  .  .
 dnl   Cygwin 1.7.0 (2009)            .  .  .  #  .  .  .  ?  .  .  .  .  .  ?  .  .  .  .  .  .
 dnl   Cygwin 1.5.25 (2008)           .  .  .  #  #  .  .  #  .  .  .  .  .  #  .  .  .  .  .  .
 dnl   Cygwin 1.5.19 (2006)           #  .  .  #  #  #  .  #  .  #  .  #  #  #  .  .  .  .  .  .
-dnl   Solaris 11 2011-11             .  .  #  #  #  .  .  #  .  .  .  #  .  .  .  .  .  .  .  .
+dnl   Solaris 11.4                   .  .  #  #  #  .  .  #  .  .  .  #  .  .  .  .  .  .  .  .
+dnl   Solaris 11.3                   .  .  .  .  #  .  .  #  .  .  .  .  .  .  .  .  .  .  .  .
+dnl   Solaris 11.0                   .  .  #  #  #  .  .  #  .  .  .  #  .  .  .  .  .  .  .  .
 dnl   Solaris 10                     .  .  #  #  #  .  .  #  .  .  .  #  #  .  .  .  .  .  .  .
 dnl   Solaris 2.6 ... 9              #  .  #  #  #  #  .  #  .  .  .  #  #  .  .  .  #  .  .  .
 dnl   Solaris 2.5.1                  #  .  #  #  #  #  .  #  .  .  .  #  .  .  #  #  #  #  #  #
@@ -1559,11 +1715,13 @@ dnl   HP-UX 10.20                    #  .  #  .  #  #  .  ?  .  .  #  #  .  .  .
 dnl   IRIX 6.5                       #  .  #  #  #  #  .  #  .  .  .  #  .  .  .  .  #  .  .  .
 dnl   OSF/1 5.1                      #  .  #  #  #  #  .  .  .  .  .  #  .  .  .  .  #  .  .  #
 dnl   OSF/1 4.0d                     #  .  #  #  #  #  .  .  .  .  .  #  .  .  #  #  #  #  #  #
+dnl   NetBSD 9.0                     .  .  .  .  #  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .
 dnl   NetBSD 5.0                     .  .  .  #  #  .  .  .  .  .  .  #  .  #  .  .  .  .  .  .
 dnl   NetBSD 4.0                     .  ?  ?  ?  ?  ?  .  ?  .  ?  ?  ?  ?  ?  .  .  .  ?  ?  ?
 dnl   NetBSD 3.0                     .  .  .  .  #  #  .  ?  #  #  ?  #  .  #  .  .  .  .  .  .
 dnl   Haiku                          .  .  .  #  #  #  .  #  .  .  .  .  .  ?  .  .  ?  .  .  .
 dnl   BeOS                           #  #  .  #  #  #  .  ?  #  .  ?  .  #  ?  .  .  ?  .  .  .
+dnl   Android 4.3                    .  .  #  #  #  #  #  #  .  #  .  #  .  #  .  .  .  #  .  .
 dnl   old mingw / msvcrt             #  #  #  #  #  #  .  .  #  #  .  #  #  ?  .  #  #  #  .  .
 dnl   MSVC 9                         #  #  #  #  #  #  #  .  #  #  .  #  #  ?  #  #  #  #  .  .
 dnl   mingw 2009-2011                .  #  .  #  .  .  .  .  #  #  .  .  .  ?  .  .  .  .  .  .
diff --git a/gl/m4/progtest.m4 b/gl/m4/progtest.m4
index 7b391232..906567bb 100644
--- a/gl/m4/progtest.m4
+++ b/gl/m4/progtest.m4
@@ -1,22 +1,22 @@
-# progtest.m4 serial 7 (gettext-0.18.2)
-dnl Copyright (C) 1996-2003, 2005, 2008-2013 Free Software Foundation, Inc.
+# progtest.m4 serial 9 (gettext-0.21.1)
+dnl Copyright (C) 1996-2003, 2005, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 dnl
-dnl This file can can be used in projects which are not available under
-dnl the GNU General Public License or the GNU Library General Public
+dnl This file can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Lesser General Public
 dnl License but which still want to provide support for the GNU gettext
 dnl functionality.
 dnl Please note that the actual code of the GNU gettext library is covered
-dnl by the GNU Library General Public License, and the rest of the GNU
-dnl gettext package package is covered by the GNU General Public License.
+dnl by the GNU Lesser General Public License, and the rest of the GNU
+dnl gettext package is covered by the GNU General Public License.
 dnl They are *not* in the public domain.
 
 dnl Authors:
 dnl   Ulrich Drepper <drepper@cygnus.com>, 1996.
 
-AC_PREREQ([2.50])
+AC_PREREQ([2.53])
 
 # Search path for a program which passes the given test.
 
@@ -61,7 +61,7 @@ AC_CACHE_VAL([ac_cv_path_$1],
     ;;
   *)
     ac_save_IFS="$IFS"; IFS=$PATH_SEPARATOR
-    for ac_dir in ifelse([$5], , $PATH, [$5]); do
+    for ac_dir in m4_if([$5], , $PATH, [$5]); do
       IFS="$ac_save_IFS"
       test -z "$ac_dir" && ac_dir=.
       for ac_exec_ext in '' $ac_executable_extensions; do
@@ -77,12 +77,12 @@ AC_CACHE_VAL([ac_cv_path_$1],
     IFS="$ac_save_IFS"
 dnl If no 4th arg is given, leave the cache variable unset,
 dnl so AC_PATH_PROGS will keep looking.
-ifelse([$4], , , [  test -z "[$]ac_cv_path_$1" && ac_cv_path_$1="$4"
+m4_if([$4], , , [  test -z "[$]ac_cv_path_$1" && ac_cv_path_$1="$4"
 ])dnl
     ;;
 esac])dnl
 $1="$ac_cv_path_$1"
-if test ifelse([$4], , [-n "[$]$1"], ["[$]$1" != "$4"]); then
+if test m4_if([$4], , [-n "[$]$1"], ["[$]$1" != "$4"]); then
   AC_MSG_RESULT([$][$1])
 else
   AC_MSG_RESULT([no])
diff --git a/gl/m4/pthread_rwlock_rdlock.m4 b/gl/m4/pthread_rwlock_rdlock.m4
new file mode 100644
index 00000000..ae6a8853
--- /dev/null
+++ b/gl/m4/pthread_rwlock_rdlock.m4
@@ -0,0 +1,185 @@
+# pthread_rwlock_rdlock.m4 serial 4
+dnl Copyright (C) 2017-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+dnl Inspired by
+dnl https://github.com/linux-test-project/ltp/blob/master/testcases/open_posix_testsuite/conformance/interfaces/pthread_rwlock_rdlock/2-2.c
+dnl by Intel Corporation.
+
+dnl Test whether in a situation where
+dnl   - an rwlock is taken by a reader and has a writer waiting,
+dnl   - an additional reader requests the lock,
+dnl   - the waiting writer and the requesting reader threads have the same
+dnl     priority,
+dnl the requesting reader thread gets blocked, so that at some point the
+dnl waiting writer can acquire the lock.
+dnl Without such a guarantee, when there a N readers and each of the readers
+dnl spends more than 1/Nth of the time with the lock held, there is a high
+dnl probability that the waiting writer will not get the lock in a given finite
+dnl time, a phenomenon called "writer starvation".
+dnl Without such a guarantee, applications have a hard time avoiding writer
+dnl starvation.
+dnl
+dnl POSIX:2017 makes this requirement only for implementations that support TPS
+dnl (Thread Priority Scheduling) and only for the scheduling policies SCHED_FIFO
+dnl and SCHED_RR, see
+dnl https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_rwlock_rdlock.html
+dnl but this test verifies the guarantee regardless of TPS and regardless of
+dnl scheduling policy.
+dnl Glibc does not provide this guarantee (and never will on Linux), see
+dnl https://sourceware.org/bugzilla/show_bug.cgi?id=13701
+dnl https://bugzilla.redhat.com/show_bug.cgi?id=1410052
+AC_DEFUN([gl_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER],
+[
+  AC_REQUIRE([gl_THREADLIB_EARLY])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether pthread_rwlock_rdlock prefers a writer to a reader],
+    [gl_cv_pthread_rwlock_rdlock_prefer_writer],
+    [save_LIBS="$LIBS"
+     LIBS="$LIBS $LIBMULTITHREAD"
+     AC_RUN_IFELSE(
+       [AC_LANG_SOURCE([[
+#include <errno.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define SUCCEED() exit (0)
+#define FAILURE() exit (1)
+#define UNEXPECTED(n) (exit (10 + (n)))
+
+/* The main thread creates the waiting writer and the requesting reader threads
+   in the default way; this guarantees that they have the same priority.
+   We can reuse the main thread as first reader thread.  */
+
+static pthread_rwlock_t lock;
+static pthread_t reader1;
+static pthread_t writer;
+static pthread_t reader2;
+static pthread_t timer;
+/* Used to pass control from writer to reader2 and from reader2 to timer,
+   as in a relay race.
+   Passing control from one running thread to another running thread
+   is most likely faster than to create the second thread.  */
+static pthread_mutex_t baton;
+
+static void *
+timer_func (void *ignored)
+{
+  /* Step 13 (can be before or after step 12):
+     The timer thread takes the baton, then waits a moment to make sure
+     it can tell whether the second reader thread is blocked at step 12.  */
+  if (pthread_mutex_lock (&baton))
+    UNEXPECTED (13);
+  usleep (100000);
+  /* By the time we get here, it's clear that the second reader thread is
+     blocked at step 12.  This is the desired behaviour.  */
+  SUCCEED ();
+}
+
+static void *
+reader2_func (void *ignored)
+{
+  int err;
+
+  /* Step 8 (can be before or after step 7):
+     The second reader thread takes the baton, then waits a moment to make sure
+     the writer thread has reached step 7.  */
+  if (pthread_mutex_lock (&baton))
+    UNEXPECTED (8);
+  usleep (100000);
+  /* Step 9: The second reader thread requests the lock.  */
+  err = pthread_rwlock_tryrdlock (&lock);
+  if (err == 0)
+    FAILURE ();
+  else if (err != EBUSY)
+    UNEXPECTED (9);
+  /* Step 10: Launch a timer, to test whether the next call blocks.  */
+  if (pthread_create (&timer, NULL, timer_func, NULL))
+    UNEXPECTED (10);
+  /* Step 11: Release the baton.  */
+  if (pthread_mutex_unlock (&baton))
+    UNEXPECTED (11);
+  /* Step 12: The second reader thread requests the lock.  */
+  err = pthread_rwlock_rdlock (&lock);
+  if (err == 0)
+    FAILURE ();
+  else
+    UNEXPECTED (12);
+}
+
+static void *
+writer_func (void *ignored)
+{
+  /* Step 4: Take the baton, so that the second reader thread does not go ahead
+     too early.  */
+  if (pthread_mutex_lock (&baton))
+    UNEXPECTED (4);
+  /* Step 5: Create the second reader thread.  */
+  if (pthread_create (&reader2, NULL, reader2_func, NULL))
+    UNEXPECTED (5);
+  /* Step 6: Release the baton.  */
+  if (pthread_mutex_unlock (&baton))
+    UNEXPECTED (6);
+  /* Step 7: The writer thread requests the lock.  */
+  if (pthread_rwlock_wrlock (&lock))
+    UNEXPECTED (7);
+  return NULL;
+}
+
+int
+main ()
+{
+  reader1 = pthread_self ();
+
+  /* Step 1: The main thread initializes the lock and the baton.  */
+  if (pthread_rwlock_init (&lock, NULL))
+    UNEXPECTED (1);
+  if (pthread_mutex_init (&baton, NULL))
+    UNEXPECTED (1);
+  /* Step 2: The main thread acquires the lock as a reader.  */
+  if (pthread_rwlock_rdlock (&lock))
+    UNEXPECTED (2);
+  /* Step 3: Create the writer thread.  */
+  if (pthread_create (&writer, NULL, writer_func, NULL))
+    UNEXPECTED (3);
+  /* Job done.  Go to sleep.  */
+  for (;;)
+    {
+      sleep (1);
+    }
+}
+]])],
+       [gl_cv_pthread_rwlock_rdlock_prefer_writer=yes],
+       [gl_cv_pthread_rwlock_rdlock_prefer_writer=no],
+       [case "$host_os" in
+                         # Guess no on glibc systems.
+          *-gnu* | gnu*) gl_cv_pthread_rwlock_rdlock_prefer_writer="guessing no" ;;
+                         # Guess no on musl systems.
+          *-musl*)       gl_cv_pthread_rwlock_rdlock_prefer_writer="guessing no" ;;
+                         # Guess no on bionic systems.
+          *-android*)    gl_cv_pthread_rwlock_rdlock_prefer_writer="guessing no" ;;
+                         # Guess yes on native Windows with the mingw-w64 winpthreads library.
+                         # Guess no on native Windows with the gnulib windows-rwlock module.
+          mingw*)        if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
+                           gl_cv_pthread_rwlock_rdlock_prefer_writer="guessing yes"
+                         else
+                           gl_cv_pthread_rwlock_rdlock_prefer_writer="guessing no"
+                         fi
+                         ;;
+                         # If we don't know, obey --enable-cross-guesses.
+          *)             gl_cv_pthread_rwlock_rdlock_prefer_writer="$gl_cross_guess_normal" ;;
+         esac
+       ])
+     LIBS="$save_LIBS"
+    ])
+  case "$gl_cv_pthread_rwlock_rdlock_prefer_writer" in
+    *yes)
+      AC_DEFINE([HAVE_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER], [1],
+        [Define if the 'pthread_rwlock_rdlock' function prefers a writer to a reader.])
+      ;;
+  esac
+])
diff --git a/gl/m4/read.m4 b/gl/m4/read.m4
deleted file mode 100644
index 81f0f3a9..00000000
--- a/gl/m4/read.m4
+++ /dev/null
@@ -1,26 +0,0 @@
-# read.m4 serial 4
-dnl Copyright (C) 2011-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-AC_DEFUN([gl_FUNC_READ],
-[
-  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
-  AC_REQUIRE([gl_MSVC_INVAL])
-  if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
-    REPLACE_READ=1
-  fi
-  dnl This ifdef is just an optimization, to avoid performing a configure
-  dnl check whose result is not used. It does not make the test of
-  dnl GNULIB_UNISTD_H_NONBLOCKING or GNULIB_NONBLOCKING redundant.
-  m4_ifdef([gl_NONBLOCKING_IO], [
-    gl_NONBLOCKING_IO
-    if test $gl_cv_have_nonblocking != yes; then
-      REPLACE_READ=1
-    fi
-  ])
-])
-
-# Prerequisites of lib/read.c.
-AC_DEFUN([gl_PREREQ_READ], [:])
diff --git a/gl/m4/realloc.m4 b/gl/m4/realloc.m4
new file mode 100644
index 00000000..d22138fc
--- /dev/null
+++ b/gl/m4/realloc.m4
@@ -0,0 +1,63 @@
+# realloc.m4 serial 26
+dnl Copyright (C) 2007, 2009-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# This is adapted with modifications from upstream Autoconf here:
+# https://git.savannah.gnu.org/cgit/autoconf.git/tree/lib/autoconf/functions.m4?id=v2.70#n1455
+AC_DEFUN([_AC_FUNC_REALLOC_IF],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
+  AC_CACHE_CHECK([whether realloc (0, 0) returns nonnull],
+    [ac_cv_func_realloc_0_nonnull],
+    [AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <stdlib.h>
+          ]],
+          [[void *p = realloc (0, 0);
+            int result = !p;
+            free (p);
+            return result;]])
+       ],
+       [ac_cv_func_realloc_0_nonnull=yes],
+       [ac_cv_func_realloc_0_nonnull=no],
+       [case "$host_os" in
+          # Guess yes on platforms where we know the result.
+          *-gnu* | freebsd* | netbsd* | openbsd* | bitrig* \
+          | gnu* | *-musl* | midnightbsd* \
+          | hpux* | solaris* | cygwin* | mingw* | msys* )
+            ac_cv_func_realloc_0_nonnull="guessing yes" ;;
+          # If we don't know, obey --enable-cross-guesses.
+          *) ac_cv_func_realloc_0_nonnull="$gl_cross_guess_normal" ;;
+        esac
+       ])
+    ])
+  AS_CASE([$ac_cv_func_realloc_0_nonnull], [*yes], [$1], [$2])
+])# AC_FUNC_REALLOC
+
+# gl_FUNC_REALLOC_GNU
+# -------------------
+# Replace realloc if it is not compatible with GNU libc.
+AC_DEFUN([gl_FUNC_REALLOC_GNU],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_REALLOC_POSIX])
+  if test $REPLACE_REALLOC_FOR_REALLOC_GNU = 0; then
+    _AC_FUNC_REALLOC_IF([], [REPLACE_REALLOC_FOR_REALLOC_GNU=1])
+  fi
+])# gl_FUNC_REALLOC_GNU
+
+# gl_FUNC_REALLOC_POSIX
+# ---------------------
+# Test whether 'realloc' is POSIX compliant (sets errno to ENOMEM when it
+# fails, and doesn't mess up with ptrdiff_t overflow),
+# and replace realloc if it is not.
+AC_DEFUN([gl_FUNC_REALLOC_POSIX],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_MALLOC_POSIX])
+  if test $REPLACE_MALLOC_FOR_MALLOC_POSIX = 1; then
+    REPLACE_REALLOC_FOR_REALLOC_POSIX=1
+  fi
+])
diff --git a/gl/m4/reallocarray.m4 b/gl/m4/reallocarray.m4
new file mode 100644
index 00000000..1607b7a9
--- /dev/null
+++ b/gl/m4/reallocarray.m4
@@ -0,0 +1,23 @@
+# reallocarray.m4 serial 3
+dnl Copyright (C) 2017-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_REALLOCARRAY],
+[
+  dnl Persuade glibc <stdlib.h> to declare reallocarray.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([gl_CHECK_MALLOC_PTRDIFF])
+  AC_CHECK_FUNCS([reallocarray])
+  if test "$ac_cv_func_reallocarray" = no; then
+    HAVE_REALLOCARRAY=0
+  elif test "$gl_cv_malloc_ptrdiff" = no; then
+    REPLACE_REALLOCARRAY=1
+  fi
+])
+
+# Prerequisites of lib/reallocarray.c.
+AC_DEFUN([gl_PREREQ_REALLOCARRAY], [:])
diff --git a/gl/m4/regex.m4 b/gl/m4/regex.m4
index 0945c11a..c89a1432 100644
--- a/gl/m4/regex.m4
+++ b/gl/m4/regex.m4
@@ -1,6 +1,6 @@
-# serial 64
+# serial 73
 
-# Copyright (C) 1996-2001, 2003-2013 Free Software Foundation, Inc.
+# Copyright (C) 1996-2001, 2003-2023 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -13,6 +13,7 @@ AC_PREREQ([2.50])
 
 AC_DEFUN([gl_REGEX],
 [
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
   AC_ARG_WITH([included-regex],
     [AS_HELP_STRING([--without-included-regex],
                     [don't compile regex; this is the default on systems
@@ -28,6 +29,7 @@ AC_DEFUN([gl_REGEX],
     # If cross compiling, assume the test would fail and use the included
     # regex.c.
     AC_CHECK_DECLS_ONCE([alarm])
+    AC_CHECK_HEADERS_ONCE([malloc.h])
     AC_CACHE_CHECK([for working re_compile_pattern],
                    [gl_cv_func_re_compile_pattern_working],
       [AC_RUN_IFELSE(
@@ -37,9 +39,19 @@ AC_DEFUN([gl_REGEX],
             #include <locale.h>
             #include <limits.h>
             #include <string.h>
-            #if HAVE_DECL_ALARM
-            # include <unistd.h>
+
+            #if defined M_CHECK_ACTION || HAVE_DECL_ALARM
             # include <signal.h>
+            # include <unistd.h>
+            #endif
+
+            #if HAVE_MALLOC_H
+            # include <malloc.h>
+            #endif
+
+            #ifdef M_CHECK_ACTION
+            /* Exit with distinguishable exit code.  */
+            static void sigabrt_no_core (int sig) { raise (SIGTERM); }
             #endif
           ]],
           [[int result = 0;
@@ -49,15 +61,22 @@ AC_DEFUN([gl_REGEX],
             const char *s;
             struct re_registers regs;
 
+            /* Some builds of glibc go into an infinite loop on this
+               test.  Use alarm to force death, and mallopt to avoid
+               malloc recursion in diagnosing the corrupted heap. */
 #if HAVE_DECL_ALARM
-            /* Some builds of glibc go into an infinite loop on this test.  */
             signal (SIGALRM, SIG_DFL);
             alarm (2);
 #endif
+#ifdef M_CHECK_ACTION
+            signal (SIGABRT, sigabrt_no_core);
+            mallopt (M_CHECK_ACTION, 2);
+#endif
+
             if (setlocale (LC_ALL, "en_US.UTF-8"))
               {
                 {
-                  /* http://sourceware.org/ml/libc-hacker/2006-09/msg00008.html
+                  /* https://sourceware.org/ml/libc-hacker/2006-09/msg00008.html
                      This test needs valgrind to catch the bug on Debian
                      GNU/Linux 3.1 x86, but it might catch the bug better
                      on other platforms and it shouldn't hurt to try the
@@ -71,16 +90,20 @@ AC_DEFUN([gl_REGEX],
                   s = re_compile_pattern (pat, sizeof pat - 1, &regex);
                   if (s)
                     result |= 1;
-                  else if (re_search (&regex, data, sizeof data - 1,
-                                      0, sizeof data - 1, &regs)
-                           != -1)
-                    result |= 1;
+                  else
+                    {
+                      if (re_search (&regex, data, sizeof data - 1,
+                                     0, sizeof data - 1, &regs)
+                          != -1)
+                        result |= 1;
+                      regfree (&regex);
+                    }
                 }
 
                 {
                   /* This test is from glibc bug 15078.
                      The test case is from Andreas Schwab in
-                     <http://www.sourceware.org/ml/libc-alpha/2013-01/msg00967.html>.
+                     <https://sourceware.org/ml/libc-alpha/2013-01/msg00967.html>.
                      */
                   static char const pat[] = "[^x]x";
                   static char const data[] =
@@ -105,6 +128,7 @@ AC_DEFUN([gl_REGEX],
                                      0, sizeof data - 1, 0);
                       if (i != 0 && i != 21)
                         result |= 1;
+                      regfree (&regex);
                     }
                 }
 
@@ -118,9 +142,13 @@ AC_DEFUN([gl_REGEX],
             s = re_compile_pattern ("a[^x]b", 6, &regex);
             if (s)
               result |= 2;
-            /* This should fail, but succeeds for glibc-2.5.  */
-            else if (re_search (&regex, "a\nb", 3, 0, 3, &regs) != -1)
-              result |= 2;
+            else
+              {
+                /* This should fail, but succeeds for glibc-2.5.  */
+                if (re_search (&regex, "a\nb", 3, 0, 3, &regs) != -1)
+                  result |= 2;
+                regfree (&regex);
+              }
 
             /* This regular expression is from Spencer ere test number 75
                in grep-2.3.  */
@@ -132,7 +160,10 @@ AC_DEFUN([gl_REGEX],
             s = re_compile_pattern ("a[[:@:>@:]]b\n", 11, &regex);
             /* This should fail with _Invalid character class name_ error.  */
             if (!s)
-              result |= 4;
+              {
+                result |= 4;
+                regfree (&regex);
+              }
 
             /* Ensure that [b-a] is diagnosed as invalid, when
                using RE_NO_EMPTY_RANGES. */
@@ -140,13 +171,18 @@ AC_DEFUN([gl_REGEX],
             memset (&regex, 0, sizeof regex);
             s = re_compile_pattern ("a[b-a]", 6, &regex);
             if (s == 0)
-              result |= 8;
+              {
+                result |= 8;
+                regfree (&regex);
+              }
 
             /* This should succeed, but does not for glibc-2.1.3.  */
             memset (&regex, 0, sizeof regex);
             s = re_compile_pattern ("{1", 2, &regex);
             if (s)
               result |= 8;
+            else
+              regfree (&regex);
 
             /* The following example is derived from a problem report
                against gawk from Jorge Stolfi <stolfi@ic.unicamp.br>.  */
@@ -154,17 +190,35 @@ AC_DEFUN([gl_REGEX],
             s = re_compile_pattern ("[an\371]*n", 7, &regex);
             if (s)
               result |= 8;
-            /* This should match, but does not for glibc-2.2.1.  */
-            else if (re_match (&regex, "an", 2, 0, &regs) != 2)
-              result |= 8;
+            else
+              {
+                /* This should match, but does not for glibc-2.2.1.  */
+                if (re_match (&regex, "an", 2, 0, &regs) != 2)
+                  result |= 8;
+                else
+                  {
+                    free (regs.start);
+                    free (regs.end);
+                  }
+                regfree (&regex);
+              }
 
             memset (&regex, 0, sizeof regex);
             s = re_compile_pattern ("x", 1, &regex);
             if (s)
               result |= 8;
-            /* glibc-2.2.93 does not work with a negative RANGE argument.  */
-            else if (re_search (&regex, "wxy", 3, 2, -2, &regs) != 1)
-              result |= 8;
+            else
+              {
+                /* glibc-2.2.93 does not work with a negative RANGE argument.  */
+                if (re_search (&regex, "wxy", 3, 2, -2, &regs) != 1)
+                  result |= 8;
+                else
+                  {
+                    free (regs.start);
+                    free (regs.end);
+                  }
+                regfree (&regex);
+              }
 
             /* The version of regex.c in older versions of gnulib
                ignored RE_ICASE.  Detect that problem too.  */
@@ -173,25 +227,89 @@ AC_DEFUN([gl_REGEX],
             s = re_compile_pattern ("x", 1, &regex);
             if (s)
               result |= 16;
-            else if (re_search (&regex, "WXY", 3, 0, 3, &regs) < 0)
-              result |= 16;
+            else
+              {
+                if (re_search (&regex, "WXY", 3, 0, 3, &regs) < 0)
+                  result |= 16;
+                else
+                  {
+                    free (regs.start);
+                    free (regs.end);
+                  }
+                regfree (&regex);
+              }
 
             /* Catch a bug reported by Vin Shelton in
-               http://lists.gnu.org/archive/html/bug-coreutils/2007-06/msg00089.html
+               https://lists.gnu.org/r/bug-coreutils/2007-06/msg00089.html
                */
             re_set_syntax (RE_SYNTAX_POSIX_BASIC
                            & ~RE_CONTEXT_INVALID_DUP
                            & ~RE_NO_EMPTY_RANGES);
             memset (&regex, 0, sizeof regex);
-            s = re_compile_pattern ("[[:alnum:]_-]\\\\+$", 16, &regex);
+            s = re_compile_pattern ("[[:alnum:]_-]\\\\+\$", 16, &regex);
             if (s)
               result |= 32;
+            else
+              regfree (&regex);
 
             /* REG_STARTEND was added to glibc on 2004-01-15.
                Reject older versions.  */
             if (! REG_STARTEND)
               result |= 64;
 
+            /* Matching with the compiled form of this regexp would provoke
+               an assertion failure prior to glibc-2.28:
+                 regexec.c:1375: pop_fail_stack: Assertion 'num >= 0' failed
+               With glibc-2.28, compilation fails and reports the invalid
+               back reference.  */
+            re_set_syntax (RE_SYNTAX_POSIX_EGREP);
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("0|()0|\\\\1|0", 10, &regex);
+            if (!s)
+              {
+                memset (&regs, 0, sizeof regs);
+                i = re_search (&regex, "x", 1, 0, 1, &regs);
+                if (i != -1)
+                  result |= 64;
+                if (0 <= i)
+                  {
+                    free (regs.start);
+                    free (regs.end);
+                  }
+                regfree (&regex);
+              }
+            else
+              {
+                if (strcmp (s, "Invalid back reference"))
+                  result |= 64;
+              }
+
+            /* glibc bug 11053.  */
+            re_set_syntax (RE_SYNTAX_POSIX_BASIC);
+            memset (&regex, 0, sizeof regex);
+            static char const pat_sub2[] = "\\\\(a*\\\\)*a*\\\\1";
+            s = re_compile_pattern (pat_sub2, sizeof pat_sub2 - 1, &regex);
+            if (s)
+              result |= 64;
+            else
+              {
+                memset (&regs, 0, sizeof regs);
+                static char const data[] = "a";
+                int datalen = sizeof data - 1;
+                i = re_search (&regex, data, datalen, 0, datalen, &regs);
+                if (i != 0)
+                  result |= 64;
+                else if (regs.num_regs < 2)
+                  result |= 64;
+                else if (! (regs.start[0] == 0 && regs.end[0] == 1))
+                  result |= 64;
+                else if (! (regs.start[1] == 0 && regs.end[1] == 0))
+                  result |= 64;
+                regfree (&regex);
+                free (regs.start);
+                free (regs.end);
+              }
+
 #if 0
             /* It would be nice to reject hosts whose regoff_t values are too
                narrow (including glibc on hosts with 64-bit ptrdiff_t and
@@ -206,13 +324,19 @@ AC_DEFUN([gl_REGEX],
 
             return result;
           ]])],
-       [gl_cv_func_re_compile_pattern_working=yes],
-       [gl_cv_func_re_compile_pattern_working=no],
-       dnl When crosscompiling, assume it is not working.
-       [gl_cv_func_re_compile_pattern_working=no])])
-    case $gl_cv_func_re_compile_pattern_working in #(
-    yes) ac_use_included_regex=no;; #(
-    no) ac_use_included_regex=yes;;
+        [gl_cv_func_re_compile_pattern_working=yes],
+        [gl_cv_func_re_compile_pattern_working=no],
+        [case "$host_os" in
+                   # Guess no on native Windows.
+           mingw*) gl_cv_func_re_compile_pattern_working="guessing no" ;;
+                   # Otherwise obey --enable-cross-guesses.
+           *)      gl_cv_func_re_compile_pattern_working="$gl_cross_guess_normal" ;;
+         esac
+        ])
+      ])
+    case "$gl_cv_func_re_compile_pattern_working" in #(
+      *yes) ac_use_included_regex=no;; #(
+      *no) ac_use_included_regex=yes;;
     esac
     ;;
   *) AC_MSG_ERROR([Invalid value for --with-included-regex: $with_included_regex])
@@ -266,8 +390,7 @@ AC_DEFUN([gl_PREREQ_REGEX],
   AC_REQUIRE([AC_C_RESTRICT])
   AC_REQUIRE([AC_TYPE_MBSTATE_T])
   AC_REQUIRE([gl_EEMALLOC])
-  AC_REQUIRE([gl_GLIBC21])
   AC_CHECK_HEADERS([libintl.h])
-  AC_CHECK_FUNCS_ONCE([isblank iswctype wcscoll])
+  AC_CHECK_FUNCS_ONCE([isblank iswctype])
   AC_CHECK_DECLS([isblank], [], [], [[#include <ctype.h>]])
 ])
diff --git a/gl/m4/safe-read.m4 b/gl/m4/safe-read.m4
deleted file mode 100644
index be5207a5..00000000
--- a/gl/m4/safe-read.m4
+++ /dev/null
@@ -1,12 +0,0 @@
-# safe-read.m4 serial 6
-dnl Copyright (C) 2002-2003, 2005-2006, 2009-2013 Free Software Foundation,
-dnl Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-# Prerequisites of lib/safe-read.c.
-AC_DEFUN([gl_PREREQ_SAFE_READ],
-[
-  AC_REQUIRE([gt_TYPE_SSIZE_T])
-])
diff --git a/gl/m4/servent.m4 b/gl/m4/servent.m4
index 01c037a8..0f35b8b8 100644
--- a/gl/m4/servent.m4
+++ b/gl/m4/servent.m4
@@ -1,5 +1,5 @@
-# servent.m4 serial 2
-dnl Copyright (C) 2008, 2010-2013 Free Software Foundation, Inc.
+# servent.m4 serial 4
+dnl Copyright (C) 2008, 2010-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -10,12 +10,12 @@ AC_DEFUN([gl_SERVENT],
   dnl getservbyport() defined?
   dnl Where are getprotoent(), setprotoent(), endprotoent(), getprotobyname(),
   dnl getprotobynumber() defined?
-  dnl - On Solaris, they are in libsocket. Ignore libxnet.
+  dnl - On Solaris < 11.4, they are in libsocket. Ignore libxnet.
   dnl - On Haiku, they are in libnetwork.
   dnl - On BeOS, they are in libnet.
   dnl - On native Windows, they are in ws2_32.dll.
   dnl - Otherwise they are in libc.
-  AC_REQUIRE([gl_HEADER_SYS_SOCKET])dnl for HAVE_SYS_SOCKET_H, HAVE_WINSOCK2_H
+  AC_REQUIRE([gl_SYS_SOCKET_H])dnl for HAVE_SYS_SOCKET_H, HAVE_WINSOCK2_H
   SERVENT_LIB=
   gl_saved_libs="$LIBS"
   AC_SEARCH_LIBS([getservbyname], [socket network net],
diff --git a/gl/m4/setenv.m4 b/gl/m4/setenv.m4
index cb5351a0..16f9eb55 100644
--- a/gl/m4/setenv.m4
+++ b/gl/m4/setenv.m4
@@ -1,5 +1,5 @@
-# setenv.m4 serial 26
-dnl Copyright (C) 2001-2004, 2006-2013 Free Software Foundation, Inc.
+# setenv.m4 serial 30
+dnl Copyright (C) 2001-2004, 2006-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -35,10 +35,12 @@ AC_DEFUN([gl_FUNC_SETENV],
       ]])],
       [gl_cv_func_setenv_works=yes], [gl_cv_func_setenv_works=no],
       [case "$host_os" in
-                 # Guess yes on glibc systems.
-         *-gnu*) gl_cv_func_setenv_works="guessing yes" ;;
-                 # If we don't know, assume the worst.
-         *)      gl_cv_func_setenv_works="guessing no" ;;
+                        # Guess yes on glibc systems.
+         *-gnu* | gnu*) gl_cv_func_setenv_works="guessing yes" ;;
+                        # Guess yes on musl systems.
+         *-musl*)       gl_cv_func_setenv_works="guessing yes" ;;
+                        # If we don't know, obey --enable-cross-guesses.
+         *)             gl_cv_func_setenv_works="$gl_cross_guess_normal" ;;
        esac
       ])])
     case "$gl_cv_func_setenv_works" in
@@ -104,35 +106,39 @@ int unsetenv (const char *name);
     dnl OpenBSD 4.7 unsetenv("") does not fail.
     AC_CACHE_CHECK([whether unsetenv obeys POSIX],
       [gl_cv_func_unsetenv_works],
-      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
-       #include <stdlib.h>
-       #include <errno.h>
-       extern char **environ;
-      ]], [[
-       char entry1[] = "a=1";
-       char entry2[] = "b=2";
-       char *env[] = { entry1, entry2, NULL };
-       if (putenv ((char *) "a=1")) return 1;
-       if (putenv (entry2)) return 2;
-       entry2[0] = 'a';
-       unsetenv ("a");
-       if (getenv ("a")) return 3;
-       if (!unsetenv ("") || errno != EINVAL) return 4;
-       entry2[0] = 'b';
-       environ = env;
-       if (!getenv ("a")) return 5;
-       entry2[0] = 'a';
-       unsetenv ("a");
-       if (getenv ("a")) return 6;
-      ]])],
-      [gl_cv_func_unsetenv_works=yes], [gl_cv_func_unsetenv_works=no],
-      [case "$host_os" in
-                 # Guess yes on glibc systems.
-         *-gnu*) gl_cv_func_unsetenv_works="guessing yes" ;;
-                 # If we don't know, assume the worst.
-         *)      gl_cv_func_unsetenv_works="guessing no" ;;
-       esac
-      ])])
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM([[
+            #include <stdlib.h>
+            #include <errno.h>
+            extern char **environ;
+           ]GL_MDA_DEFINES],
+           [[
+            char entry1[] = "a=1";
+            char entry2[] = "b=2";
+            char *env[] = { entry1, entry2, NULL };
+            if (putenv ((char *) "a=1")) return 1;
+            if (putenv (entry2)) return 2;
+            entry2[0] = 'a';
+            unsetenv ("a");
+            if (getenv ("a")) return 3;
+            if (!unsetenv ("") || errno != EINVAL) return 4;
+            entry2[0] = 'b';
+            environ = env;
+            if (!getenv ("a")) return 5;
+            entry2[0] = 'a';
+            unsetenv ("a");
+            if (getenv ("a")) return 6;
+           ]])],
+         [gl_cv_func_unsetenv_works=yes],
+         [gl_cv_func_unsetenv_works=no],
+         [case "$host_os" in
+                    # Guess yes on glibc systems.
+            *-gnu*) gl_cv_func_unsetenv_works="guessing yes" ;;
+                    # If we don't know, obey --enable-cross-guesses.
+            *)      gl_cv_func_unsetenv_works="$gl_cross_guess_normal" ;;
+          esac
+         ])
+      ])
     case "$gl_cv_func_unsetenv_works" in
       *yes) ;;
       *)
diff --git a/gl/m4/setlocale_null.m4 b/gl/m4/setlocale_null.m4
new file mode 100644
index 00000000..032119d0
--- /dev/null
+++ b/gl/m4/setlocale_null.m4
@@ -0,0 +1,98 @@
+# setlocale_null.m4 serial 5
+dnl Copyright (C) 2019-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_SETLOCALE_NULL],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_PTHREADLIB])
+  AC_CHECK_HEADERS_ONCE([threads.h])
+
+  AC_CACHE_CHECK([whether setlocale (LC_ALL, NULL) is multithread-safe],
+    [gl_cv_func_setlocale_null_all_mtsafe],
+    [case "$host_os" in
+       # Guess no on musl libc, macOS, FreeBSD, NetBSD, OpenBSD, AIX, Haiku, Cygwin.
+       *-musl* | darwin* | freebsd* | midnightbsd* | netbsd* | openbsd* | aix* | haiku* | cygwin*)
+         gl_cv_func_setlocale_null_all_mtsafe=no ;;
+       # Guess yes on glibc, HP-UX, IRIX, Solaris, native Windows.
+       *-gnu* | gnu* | hpux* | irix* | solaris* | mingw*)
+         gl_cv_func_setlocale_null_all_mtsafe=yes ;;
+       # If we don't know, obey --enable-cross-guesses.
+       *)
+         gl_cv_func_setlocale_null_all_mtsafe="$gl_cross_guess_normal" ;;
+     esac
+    ])
+  dnl On platforms without multithreading, there is no issue.
+  case "$host_os" in
+    mingw*) ;;
+    *)
+      if test $gl_pthread_api = no && test $ac_cv_header_threads_h = no; then
+        gl_cv_func_setlocale_null_all_mtsafe="trivially yes"
+      fi
+      ;;
+  esac
+  case "$gl_cv_func_setlocale_null_all_mtsafe" in
+    *yes) SETLOCALE_NULL_ALL_MTSAFE=1 ;;
+    *)    SETLOCALE_NULL_ALL_MTSAFE=0 ;;
+  esac
+  AC_DEFINE_UNQUOTED([SETLOCALE_NULL_ALL_MTSAFE], [$SETLOCALE_NULL_ALL_MTSAFE],
+    [Define to 1 if setlocale (LC_ALL, NULL) is multithread-safe.])
+
+  dnl This is about a single category (not LC_ALL).
+  AC_CACHE_CHECK([whether setlocale (category, NULL) is multithread-safe],
+    [gl_cv_func_setlocale_null_one_mtsafe],
+    [case "$host_os" in
+       # Guess no on OpenBSD, AIX.
+       openbsd* | aix*)
+         gl_cv_func_setlocale_null_one_mtsafe=no ;;
+       # Guess yes on glibc, musl libc, macOS, FreeBSD, NetBSD, HP-UX, IRIX, Solaris, Haiku, Cygwin, native Windows.
+       *-gnu* | gnu* | *-musl* | darwin* | freebsd* | midnightbsd* | netbsd* | hpux* | irix* | solaris* | haiku* | cygwin* | mingw*)
+         gl_cv_func_setlocale_null_one_mtsafe=yes ;;
+       # If we don't know, obey --enable-cross-guesses.
+       *)
+         gl_cv_func_setlocale_null_one_mtsafe="$gl_cross_guess_normal" ;;
+     esac
+    ])
+  dnl On platforms without multithreading, there is no issue.
+  case "$host_os" in
+    mingw*) ;;
+    *)
+      if test $gl_pthread_api = no && test $ac_cv_header_threads_h = no; then
+        gl_cv_func_setlocale_null_one_mtsafe="trivially yes"
+      fi
+      ;;
+  esac
+  case "$gl_cv_func_setlocale_null_one_mtsafe" in
+    *yes) SETLOCALE_NULL_ONE_MTSAFE=1 ;;
+    *)    SETLOCALE_NULL_ONE_MTSAFE=0 ;;
+  esac
+  AC_DEFINE_UNQUOTED([SETLOCALE_NULL_ONE_MTSAFE], [$SETLOCALE_NULL_ONE_MTSAFE],
+    [Define to 1 if setlocale (category, NULL) is multithread-safe.])
+
+  dnl Determine link dependencies of lib/setlocale_null.c and lib/setlocale-lock.c.
+  if test $SETLOCALE_NULL_ALL_MTSAFE = 0 || test $SETLOCALE_NULL_ONE_MTSAFE = 0; then
+    case "$host_os" in
+      mingw*) LIB_SETLOCALE_NULL= ;;
+      *)
+        gl_WEAK_SYMBOLS
+        case "$gl_cv_have_weak" in
+          *yes) LIB_SETLOCALE_NULL= ;;
+          *)    LIB_SETLOCALE_NULL="$LIBPTHREAD" ;;
+        esac
+        ;;
+    esac
+  else
+    LIB_SETLOCALE_NULL=
+  fi
+  dnl LIB_SETLOCALE_NULL is expected to be '-pthread' or '-lpthread' on AIX
+  dnl with gcc or xlc, and empty otherwise.
+  AC_SUBST([LIB_SETLOCALE_NULL])
+])
+
+# Prerequisites of lib/setlocale-lock.c.
+AC_DEFUN([gl_PREREQ_SETLOCALE_LOCK],
+[
+  gl_VISIBILITY
+])
diff --git a/gl/m4/sha1.m4 b/gl/m4/sha1.m4
index 21c775e3..16b79c08 100644
--- a/gl/m4/sha1.m4
+++ b/gl/m4/sha1.m4
@@ -1,5 +1,5 @@
-# sha1.m4 serial 11
-dnl Copyright (C) 2002-2006, 2008-2013 Free Software Foundation, Inc.
+# sha1.m4 serial 12
+dnl Copyright (C) 2002-2006, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -8,5 +8,7 @@ AC_DEFUN([gl_SHA1],
 [
   dnl Prerequisites of lib/sha1.c.
   AC_REQUIRE([gl_BIGENDIAN])
-  :
+
+  dnl Determine HAVE_OPENSSL_SHA1 and LIB_CRYPTO
+  gl_CRYPTO_CHECK([SHA1])
 ])
diff --git a/gl/m4/size_max.m4 b/gl/m4/size_max.m4
index 4b247abc..0763366d 100644
--- a/gl/m4/size_max.m4
+++ b/gl/m4/size_max.m4
@@ -1,17 +1,19 @@
-# size_max.m4 serial 10
-dnl Copyright (C) 2003, 2005-2006, 2008-2013 Free Software Foundation, Inc.
+# size_max.m4 serial 12
+dnl Copyright (C) 2003, 2005-2006, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl From Bruno Haible.
 
+AC_PREREQ([2.61])
+
 AC_DEFUN([gl_SIZE_MAX],
 [
   AC_CHECK_HEADERS([stdint.h])
   dnl First test whether the system already has SIZE_MAX.
   AC_CACHE_CHECK([for SIZE_MAX], [gl_cv_size_max], [
-    gl_cv_size_max=
+    gl_cv_size_max=no
     AC_EGREP_CPP([Found it], [
 #include <limits.h>
 #if HAVE_STDINT_H
@@ -21,7 +23,7 @@ AC_DEFUN([gl_SIZE_MAX],
 Found it
 #endif
 ], [gl_cv_size_max=yes])
-    if test -z "$gl_cv_size_max"; then
+    if test $gl_cv_size_max != yes; then
       dnl Define it ourselves. Here we assume that the type 'size_t' is not wider
       dnl than the type 'unsigned long'. Try hard to find a definition that can
       dnl be used in a preprocessor #if, i.e. doesn't contain a cast.
@@ -71,9 +73,3 @@ Found it
 # undef SIZE_MAX
 #endif])
 ])
-
-dnl Autoconf >= 2.61 has AC_COMPUTE_INT built-in.
-dnl Remove this when we can assume autoconf >= 2.61.
-m4_ifdef([AC_COMPUTE_INT], [], [
-  AC_DEFUN([AC_COMPUTE_INT], [_AC_COMPUTE_INT([$2],[$1],[$3],[$4])])
-])
diff --git a/gl/m4/snprintf.m4 b/gl/m4/snprintf.m4
index 3698e844..4b5fbdbf 100644
--- a/gl/m4/snprintf.m4
+++ b/gl/m4/snprintf.m4
@@ -1,5 +1,5 @@
-# snprintf.m4 serial 6
-dnl Copyright (C) 2002-2004, 2007-2013 Free Software Foundation, Inc.
+# snprintf.m4 serial 7
+dnl Copyright (C) 2002-2004, 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -46,6 +46,14 @@ AC_DEFUN([gl_REPLACE_SNPRINTF],
   AC_LIBOBJ([snprintf])
   if test $ac_cv_func_snprintf = yes; then
     REPLACE_SNPRINTF=1
+  else
+    AC_CHECK_DECLS_ONCE([snprintf])
+    if test $ac_cv_have_decl_snprintf = yes; then
+      dnl If the function is declared but does not appear to exist, it may be
+      dnl defined as an inline function. In order to avoid a conflict, we have
+      dnl to define rpl_snprintf, not snprintf.
+      REPLACE_SNPRINTF=1
+    fi
   fi
   gl_PREREQ_SNPRINTF
 ])
diff --git a/gl/m4/socketlib.m4 b/gl/m4/socketlib.m4
index b08a72f6..a556af1e 100644
--- a/gl/m4/socketlib.m4
+++ b/gl/m4/socketlib.m4
@@ -1,5 +1,5 @@
-# socketlib.m4 serial 1
-dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
+# socketlib.m4 serial 3
+dnl Copyright (C) 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -14,21 +14,27 @@ AC_DEFUN([gl_SOCKETLIB],
   LIBSOCKET=
   if test $HAVE_WINSOCK2_H = 1; then
     dnl Native Windows API (not Cygwin).
-    AC_CACHE_CHECK([if we need to call WSAStartup in winsock2.h and -lws2_32],
-                   [gl_cv_func_wsastartup], [
-      gl_save_LIBS="$LIBS"
-      LIBS="$LIBS -lws2_32"
-      AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+    dnl If the function WSAStartup exists (declared in <winsock2.h> and
+    dnl defined through -lws2_32), we need to call it.
+    AC_CACHE_CHECK([for WSAStartup],
+      [gl_cv_func_wsastartup], [
+       gl_save_LIBS="$LIBS"
+       LIBS="$LIBS -lws2_32"
+       AC_LINK_IFELSE(
+         [AC_LANG_PROGRAM([[
 #ifdef HAVE_WINSOCK2_H
 # include <winsock2.h>
 #endif]], [[
-          WORD wVersionRequested = MAKEWORD(1, 1);
-          WSADATA wsaData;
-          int err = WSAStartup(wVersionRequested, &wsaData);
-          WSACleanup ();]])],
-        gl_cv_func_wsastartup=yes, gl_cv_func_wsastartup=no)
-      LIBS="$gl_save_LIBS"
-    ])
+            WORD wVersionRequested = MAKEWORD(1, 1);
+            WSADATA wsaData;
+            int err = WSAStartup(wVersionRequested, &wsaData);
+            WSACleanup ();
+            ]])
+         ],
+         [gl_cv_func_wsastartup=yes],
+         [gl_cv_func_wsastartup=no])
+       LIBS="$gl_save_LIBS"
+      ])
     if test "$gl_cv_func_wsastartup" = "yes"; then
       AC_DEFINE([WINDOWS_SOCKETS], [1], [Define if WSAStartup is needed.])
       LIBSOCKET='-lws2_32'
@@ -38,6 +44,10 @@ AC_DEFUN([gl_SOCKETLIB],
     dnl Solaris has most socket functions in libsocket.
     dnl Haiku has most socket functions in libnetwork.
     dnl BeOS has most socket functions in libnet.
+    dnl On HP-UX, do NOT link with libxnet, because in 64-bit mode this would
+    dnl break code (e.g. in libraries) that invokes accept(), getpeername(),
+    dnl getsockname(), getsockopt(), or recvfrom() with a 32-bit addrlen. See
+    dnl "man xopen_networking" for details.
     AC_CACHE_CHECK([for library containing setsockopt], [gl_cv_lib_socket], [
       gl_cv_lib_socket=
       AC_LINK_IFELSE([AC_LANG_PROGRAM([[extern
diff --git a/gl/m4/sockets.m4 b/gl/m4/sockets.m4
index b407391c..ed9cb873 100644
--- a/gl/m4/sockets.m4
+++ b/gl/m4/sockets.m4
@@ -1,5 +1,5 @@
 # sockets.m4 serial 7
-dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/socklen.m4 b/gl/m4/socklen.m4
index e3efd6ef..1c63a853 100644
--- a/gl/m4/socklen.m4
+++ b/gl/m4/socklen.m4
@@ -1,5 +1,5 @@
-# socklen.m4 serial 10
-dnl Copyright (C) 2005-2007, 2009-2013 Free Software Foundation, Inc.
+# socklen.m4 serial 11
+dnl Copyright (C) 2005-2007, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -15,8 +15,8 @@ dnl So we have to test to find something that will work.
 AC_DEFUN([gl_TYPE_SOCKLEN_T],
   [AC_REQUIRE([gl_CHECK_SOCKET_HEADERS])dnl
    AC_CHECK_TYPE([socklen_t], ,
-     [AC_MSG_CHECKING([for socklen_t equivalent])
-      AC_CACHE_VAL([gl_cv_socklen_t_equiv],
+     [AC_CACHE_CHECK([for socklen_t equivalent],
+        [gl_cv_socklen_t_equiv],
         [# Systems have either "struct sockaddr *" or
          # "void *" as the second argument to getpeername
          gl_cv_socklen_t_equiv=
@@ -34,11 +34,10 @@ AC_DEFUN([gl_TYPE_SOCKLEN_T],
            done
            test "$gl_cv_socklen_t_equiv" != "" && break
          done
-      ])
-      if test "$gl_cv_socklen_t_equiv" = ""; then
-        AC_MSG_ERROR([Cannot find a type to use in place of socklen_t])
-      fi
-      AC_MSG_RESULT([$gl_cv_socklen_t_equiv])
+         if test "$gl_cv_socklen_t_equiv" = ""; then
+           AC_MSG_ERROR([Cannot find a type to use in place of socklen_t])
+         fi
+        ])
       AC_DEFINE_UNQUOTED([socklen_t], [$gl_cv_socklen_t_equiv],
         [type to use in place of socklen_t if not defined])],
      [gl_SOCKET_HEADERS])])
diff --git a/gl/m4/sockpfaf.m4 b/gl/m4/sockpfaf.m4
index 89557b18..6c6dc2f7 100644
--- a/gl/m4/sockpfaf.m4
+++ b/gl/m4/sockpfaf.m4
@@ -1,5 +1,5 @@
-# sockpfaf.m4 serial 8
-dnl Copyright (C) 2004, 2006, 2009-2013 Free Software Foundation, Inc.
+# sockpfaf.m4 serial 10
+dnl Copyright (C) 2004, 2006, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -13,11 +13,11 @@ dnl From Bruno Haible.
 
 AC_DEFUN([gl_SOCKET_FAMILIES],
 [
-  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  AC_REQUIRE([gl_SYS_SOCKET_H])
   AC_CHECK_HEADERS_ONCE([netinet/in.h])
 
-  AC_MSG_CHECKING([for IPv4 sockets])
-  AC_CACHE_VAL([gl_cv_socket_ipv4],
+  AC_CACHE_CHECK([for IPv4 sockets],
+    [gl_cv_socket_ipv4],
     [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>
 #ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
@@ -31,13 +31,12 @@ AC_DEFUN([gl_SOCKET_FAMILIES],
 [[int x = AF_INET; struct in_addr y; struct sockaddr_in z;
  if (&x && &y && &z) return 0;]])],
        gl_cv_socket_ipv4=yes, gl_cv_socket_ipv4=no)])
-  AC_MSG_RESULT([$gl_cv_socket_ipv4])
   if test $gl_cv_socket_ipv4 = yes; then
     AC_DEFINE([HAVE_IPV4], [1], [Define to 1 if <sys/socket.h> defines AF_INET.])
   fi
 
-  AC_MSG_CHECKING([for IPv6 sockets])
-  AC_CACHE_VAL([gl_cv_socket_ipv6],
+  AC_CACHE_CHECK([for IPv6 sockets],
+    [gl_cv_socket_ipv6],
     [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>
 #ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
@@ -54,7 +53,6 @@ AC_DEFUN([gl_SOCKET_FAMILIES],
 [[int x = AF_INET6; struct in6_addr y; struct sockaddr_in6 z;
  if (&x && &y && &z) return 0;]])],
        gl_cv_socket_ipv6=yes, gl_cv_socket_ipv6=no)])
-  AC_MSG_RESULT([$gl_cv_socket_ipv6])
   if test $gl_cv_socket_ipv6 = yes; then
     AC_DEFINE([HAVE_IPV6], [1], [Define to 1 if <sys/socket.h> defines AF_INET6.])
   fi
@@ -62,11 +60,11 @@ AC_DEFUN([gl_SOCKET_FAMILIES],
 
 AC_DEFUN([gl_SOCKET_FAMILY_UNIX],
 [
-  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  AC_REQUIRE([gl_SYS_SOCKET_H])
   AC_CHECK_HEADERS_ONCE([sys/un.h])
 
-  AC_MSG_CHECKING([for UNIX domain sockets])
-  AC_CACHE_VAL([gl_cv_socket_unix],
+  AC_CACHE_CHECK([for UNIX domain sockets],
+    [gl_cv_socket_unix],
     [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>
 #ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
@@ -80,7 +78,6 @@ AC_DEFUN([gl_SOCKET_FAMILY_UNIX],
 [[int x = AF_UNIX; struct sockaddr_un y;
  if (&x && &y) return 0;]])],
        gl_cv_socket_unix=yes, gl_cv_socket_unix=no)])
-  AC_MSG_RESULT([$gl_cv_socket_unix])
   if test $gl_cv_socket_unix = yes; then
     AC_DEFINE([HAVE_UNIXSOCKET], [1], [Define to 1 if <sys/socket.h> defines AF_UNIX.])
   fi
diff --git a/gl/m4/ssize_t.m4 b/gl/m4/ssize_t.m4
index 63381343..1c12c33e 100644
--- a/gl/m4/ssize_t.m4
+++ b/gl/m4/ssize_t.m4
@@ -1,5 +1,5 @@
 # ssize_t.m4 serial 5 (gettext-0.18.2)
-dnl Copyright (C) 2001-2003, 2006, 2010-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2001-2003, 2006, 2010-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/stat-time.m4 b/gl/m4/stat-time.m4
new file mode 100644
index 00000000..40993d57
--- /dev/null
+++ b/gl/m4/stat-time.m4
@@ -0,0 +1,83 @@
+# Checks for stat-related time functions.
+
+# Copyright (C) 1998-1999, 2001, 2003, 2005-2007, 2009-2023 Free Software
+# Foundation, Inc.
+
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl From Paul Eggert.
+
+# st_atim.tv_nsec - Linux, Solaris, Cygwin
+# st_atimespec.tv_nsec - FreeBSD, NetBSD, if ! defined _POSIX_SOURCE
+# st_atimensec - FreeBSD, NetBSD, if defined _POSIX_SOURCE
+# st_atim.st__tim.tv_nsec - UnixWare (at least 2.1.2 through 7.1)
+
+# st_birthtimespec - FreeBSD, NetBSD (hidden on OpenBSD 3.9, anyway)
+# st_birthtim - Cygwin 1.7.0+
+
+AC_DEFUN([gl_STAT_TIME],
+[
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_CHECK_HEADERS_ONCE([sys/time.h])
+
+  AC_CHECK_MEMBERS([struct stat.st_atim.tv_nsec],
+    [AC_CACHE_CHECK([whether struct stat.st_atim is of type struct timespec],
+       [ac_cv_typeof_struct_stat_st_atim_is_struct_timespec],
+       [AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
+          [[
+            #include <sys/types.h>
+            #include <sys/stat.h>
+            #if HAVE_SYS_TIME_H
+            # include <sys/time.h>
+            #endif
+            #include <time.h>
+            struct timespec ts;
+            struct stat st;
+          ]],
+          [[
+            st.st_atim = ts;
+          ]])],
+          [ac_cv_typeof_struct_stat_st_atim_is_struct_timespec=yes],
+          [ac_cv_typeof_struct_stat_st_atim_is_struct_timespec=no])])
+     if test $ac_cv_typeof_struct_stat_st_atim_is_struct_timespec = yes; then
+       AC_DEFINE([TYPEOF_STRUCT_STAT_ST_ATIM_IS_STRUCT_TIMESPEC], [1],
+         [Define to 1 if the type of the st_atim member of a struct stat is
+          struct timespec.])
+     fi],
+    [AC_CHECK_MEMBERS([struct stat.st_atimespec.tv_nsec], [],
+       [AC_CHECK_MEMBERS([struct stat.st_atimensec], [],
+          [AC_CHECK_MEMBERS([struct stat.st_atim.st__tim.tv_nsec], [], [],
+             [#include <sys/types.h>
+              #include <sys/stat.h>])],
+          [#include <sys/types.h>
+           #include <sys/stat.h>])],
+       [#include <sys/types.h>
+        #include <sys/stat.h>])],
+    [#include <sys/types.h>
+     #include <sys/stat.h>])
+])
+
+# Check for st_birthtime, a feature from UFS2 (FreeBSD, NetBSD, OpenBSD, etc.)
+# and NTFS (Cygwin).
+# There was a time when this field was named st_createtime (21 June
+# 2002 to 16 July 2002) But that window is very small and applied only
+# to development code, so systems still using that configuration are
+# not supported.  See revisions 1.10 and 1.11 of FreeBSD's
+# src/sys/ufs/ufs/dinode.h.
+#
+AC_DEFUN([gl_STAT_BIRTHTIME],
+[
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_CHECK_HEADERS_ONCE([sys/time.h])
+  AC_CHECK_MEMBERS([struct stat.st_birthtimespec.tv_nsec], [],
+    [AC_CHECK_MEMBERS([struct stat.st_birthtimensec], [],
+      [AC_CHECK_MEMBERS([struct stat.st_birthtim.tv_nsec], [], [],
+         [#include <sys/types.h>
+          #include <sys/stat.h>])],
+       [#include <sys/types.h>
+        #include <sys/stat.h>])],
+    [#include <sys/types.h>
+     #include <sys/stat.h>])
+])
diff --git a/gl/m4/stat.m4 b/gl/m4/stat.m4
new file mode 100644
index 00000000..4d241e27
--- /dev/null
+++ b/gl/m4/stat.m4
@@ -0,0 +1,85 @@
+# serial 18
+
+# Copyright (C) 2009-2023 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_STAT],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([lstat])
+  case "$host_os" in
+    mingw*)
+      dnl On this platform, the original stat() returns st_atime, st_mtime,
+      dnl st_ctime values that are affected by the time zone.
+      REPLACE_STAT=1
+      ;;
+    *)
+      dnl AIX 7.1, Solaris 9, mingw64 mistakenly succeed on stat("file/").
+      dnl (For mingw, this is due to a broken stat() override in libmingwex.a.)
+      dnl FreeBSD 7.2 mistakenly succeeds on stat("link-to-file/").
+      AC_CACHE_CHECK([whether stat handles trailing slashes on files],
+        [gl_cv_func_stat_file_slash],
+        [touch conftest.tmp
+         # Assume that if we have lstat, we can also check symlinks.
+         if test $ac_cv_func_lstat = yes; then
+           ln -s conftest.tmp conftest.lnk
+         fi
+         AC_RUN_IFELSE(
+           [AC_LANG_PROGRAM(
+             [[#include <sys/stat.h>
+]], [[int result = 0;
+               struct stat st;
+               if (!stat ("conftest.tmp/", &st))
+                 result |= 1;
+#if HAVE_LSTAT
+               if (!stat ("conftest.lnk/", &st))
+                 result |= 2;
+#endif
+               return result;
+             ]])],
+           [gl_cv_func_stat_file_slash=yes], [gl_cv_func_stat_file_slash=no],
+           [case "$host_os" in
+                               # Guess yes on Linux systems.
+              linux-* | linux) gl_cv_func_stat_file_slash="guessing yes" ;;
+                               # Guess yes on glibc systems.
+              *-gnu* | gnu*)   gl_cv_func_stat_file_slash="guessing yes" ;;
+                               # If we don't know, obey --enable-cross-guesses.
+              *)               gl_cv_func_stat_file_slash="$gl_cross_guess_normal" ;;
+            esac
+           ])
+         rm -f conftest.tmp conftest.lnk])
+      case $gl_cv_func_stat_file_slash in
+        *no)
+          REPLACE_STAT=1
+          AC_DEFINE([REPLACE_FUNC_STAT_FILE], [1], [Define to 1 if stat needs
+            help when passed a file name with a trailing slash]);;
+      esac
+      case $host_os in
+        dnl Solaris stat can return a negative tv_nsec.
+        solaris*)
+          REPLACE_FSTAT=1 ;;
+      esac
+      ;;
+  esac
+])
+
+# Prerequisites of lib/stat.c and lib/stat-w32.c.
+AC_DEFUN([gl_PREREQ_STAT], [
+  AC_REQUIRE([gl_SYS_STAT_H])
+  AC_REQUIRE([gl_PREREQ_STAT_W32])
+  :
+])
+
+# Prerequisites of lib/stat-w32.c.
+AC_DEFUN([gl_PREREQ_STAT_W32], [
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw*)
+      AC_CHECK_HEADERS([sdkddkver.h])
+      ;;
+  esac
+])
diff --git a/gl/m4/std-gnu11.m4 b/gl/m4/std-gnu11.m4
new file mode 100644
index 00000000..4179470e
--- /dev/null
+++ b/gl/m4/std-gnu11.m4
@@ -0,0 +1,829 @@
+# Prefer GNU C11 and C++11 to earlier versions.  -*- coding: utf-8 -*-
+
+# This implementation is taken from GNU Autoconf lib/autoconf/c.m4
+# commit 017d5ddd82854911f0119691d91ea8a1438824d6
+# dated Sun Apr 3 13:57:17 2016 -0700
+# This implementation will be obsolete once we can assume Autoconf 2.70
+# or later is installed everywhere a Gnulib program might be developed.
+
+m4_version_prereq([2.70], [], [
+
+
+# Copyright (C) 2001-2023 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# Written by David MacKenzie, with help from
+# Akim Demaille, Paul Eggert,
+# François Pinard, Karl Berry, Richard Pixley, Ian Lance Taylor,
+# Roland McGrath, Noah Friedman, david d zuhn, and many others.
+
+
+# AC_PROG_CC([COMPILER ...])
+# --------------------------
+# COMPILER ... is a space separated list of C compilers to search for.
+# This just gives the user an opportunity to specify an alternative
+# search list for the C compiler.
+AC_DEFUN_ONCE([AC_PROG_CC],
+[AC_LANG_PUSH(C)dnl
+AC_ARG_VAR([CC],     [C compiler command])dnl
+AC_ARG_VAR([CFLAGS], [C compiler flags])dnl
+_AC_ARG_VAR_LDFLAGS()dnl
+_AC_ARG_VAR_LIBS()dnl
+_AC_ARG_VAR_CPPFLAGS()dnl
+m4_ifval([$1],
+      [AC_CHECK_TOOLS(CC, [$1])],
+[AC_CHECK_TOOL(CC, gcc)
+if test -z "$CC"; then
+  dnl Here we want:
+  dnl   AC_CHECK_TOOL(CC, cc)
+  dnl but without the check for a tool without the prefix.
+  dnl Until the check is removed from there, copy the code:
+  if test -n "$ac_tool_prefix"; then
+    AC_CHECK_PROG(CC, [${ac_tool_prefix}cc], [${ac_tool_prefix}cc])
+  fi
+fi
+if test -z "$CC"; then
+  AC_CHECK_PROG(CC, cc, cc, , , /usr/ucb/cc)
+fi
+if test -z "$CC"; then
+  AC_CHECK_TOOLS(CC, cl.exe)
+fi
+if test -z "$CC"; then
+  AC_CHECK_TOOL(CC, clang)
+fi
+])
+
+test -z "$CC" && AC_MSG_FAILURE([no acceptable C compiler found in \$PATH])
+
+# Provide some information about the compiler.
+_AS_ECHO_LOG([checking for _AC_LANG compiler version])
+set X $ac_compile
+ac_compiler=$[2]
+for ac_option in --version -v -V -qversion -version; do
+  _AC_DO_LIMIT([$ac_compiler $ac_option >&AS_MESSAGE_LOG_FD])
+done
+
+m4_expand_once([_AC_COMPILER_EXEEXT])[]dnl
+m4_expand_once([_AC_COMPILER_OBJEXT])[]dnl
+_AC_LANG_COMPILER_GNU
+if test $ac_compiler_gnu = yes; then
+  GCC=yes
+else
+  GCC=
+fi
+_AC_PROG_CC_G
+dnl
+dnl Set ac_prog_cc_stdc to the supported C version.
+dnl Also set the documented variable ac_cv_prog_cc_stdc;
+dnl its name was chosen when it was cached, but it is no longer cached.
+_AC_PROG_CC_C11([ac_prog_cc_stdc=c11
+                 ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c11],
+  [_AC_PROG_CC_C99([ac_prog_cc_stdc=c99
+                    ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c99],
+     [_AC_PROG_CC_C89([ac_prog_cc_stdc=c89
+                       ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c89],
+                      [ac_prog_cc_stdc=no
+                       ac_cv_prog_cc_stdc=no])])])
+dnl
+AC_LANG_POP(C)dnl
+])# AC_PROG_CC
+
+
+
+# AC_PROG_CXX([LIST-OF-COMPILERS])
+# --------------------------------
+# LIST-OF-COMPILERS is a space separated list of C++ compilers to search
+# for (if not specified, a default list is used).  This just gives the
+# user an opportunity to specify an alternative search list for the C++
+# compiler.
+# aCC   HP-UX C++ compiler much better than `CC', so test before.
+# FCC   Fujitsu C++ compiler
+# KCC   KAI C++ compiler
+# RCC   Rational C++
+# xlC_r AIX C Set++ (with support for reentrant code)
+# xlC   AIX C Set++
+AC_DEFUN([AC_PROG_CXX],
+[AC_LANG_PUSH(C++)dnl
+AC_ARG_VAR([CXX],      [C++ compiler command])dnl
+AC_ARG_VAR([CXXFLAGS], [C++ compiler flags])dnl
+_AC_ARG_VAR_LDFLAGS()dnl
+_AC_ARG_VAR_LIBS()dnl
+_AC_ARG_VAR_CPPFLAGS()dnl
+_AC_ARG_VAR_PRECIOUS([CCC])dnl
+if test -z "$CXX"; then
+  if test -n "$CCC"; then
+    CXX=$CCC
+  else
+    AC_CHECK_TOOLS(CXX,
+                   [m4_default([$1],
+                               [g++ c++ gpp aCC CC cxx cc++ cl.exe FCC KCC RCC xlC_r xlC clang++])],
+                   g++)
+  fi
+fi
+# Provide some information about the compiler.
+_AS_ECHO_LOG([checking for _AC_LANG compiler version])
+set X $ac_compile
+ac_compiler=$[2]
+for ac_option in --version -v -V -qversion; do
+  _AC_DO_LIMIT([$ac_compiler $ac_option >&AS_MESSAGE_LOG_FD])
+done
+
+m4_expand_once([_AC_COMPILER_EXEEXT])[]dnl
+m4_expand_once([_AC_COMPILER_OBJEXT])[]dnl
+_AC_LANG_COMPILER_GNU
+if test $ac_compiler_gnu = yes; then
+  GXX=yes
+else
+  GXX=
+fi
+_AC_PROG_CXX_G
+_AC_PROG_CXX_CXX11([ac_prog_cxx_stdcxx=cxx11
+                    ac_cv_prog_cxx_stdcxx=$ac_cv_prog_cxx_cxx11
+                    ac_cv_prog_cxx_cxx98=$ac_cv_prog_cxx_cxx11],
+   [_AC_PROG_CXX_CXX98([ac_prog_cxx_stdcxx=cxx98
+                        ac_cv_prog_cxx_stdcxx=$ac_cv_prog_cxx_cxx98],
+                       [ac_prog_cxx_stdcxx=no
+                        ac_cv_prog_cxx_stdcxx=no])])
+AC_LANG_POP(C++)dnl
+])# AC_PROG_CXX
+
+
+# _AC_C_STD_TRY(STANDARD, TEST-PROLOGUE, TEST-BODY, OPTION-LIST,
+#               ACTION-IF-AVAILABLE, ACTION-IF-UNAVAILABLE)
+# --------------------------------------------------------------
+# Check whether the C compiler accepts features of STANDARD (e.g `c89', `c99')
+# by trying to compile a program of TEST-PROLOGUE and TEST-BODY.  If this fails,
+# try again with each compiler option in the space-separated OPTION-LIST; if one
+# helps, append it to CC.  If eventually successful, run ACTION-IF-AVAILABLE,
+# else ACTION-IF-UNAVAILABLE.
+AC_DEFUN([_AC_C_STD_TRY],
+[AC_MSG_CHECKING([for $CC option to enable ]m4_translit($1, [c], [C])[ features])
+AC_CACHE_VAL(ac_cv_prog_cc_$1,
+[ac_cv_prog_cc_$1=no
+ac_save_CC=$CC
+AC_LANG_CONFTEST([AC_LANG_PROGRAM([$2], [$3])])
+for ac_arg in '' $4
+do
+  CC="$ac_save_CC $ac_arg"
+  _AC_COMPILE_IFELSE([], [ac_cv_prog_cc_$1=$ac_arg])
+  test "x$ac_cv_prog_cc_$1" != "xno" && break
+done
+rm -f conftest.$ac_ext
+CC=$ac_save_CC
+])# AC_CACHE_VAL
+ac_prog_cc_stdc_options=
+case "x$ac_cv_prog_cc_$1" in
+  x)
+    AC_MSG_RESULT([none needed]) ;;
+  xno)
+    AC_MSG_RESULT([unsupported]) ;;
+  *)
+    ac_prog_cc_stdc_options=" $ac_cv_prog_cc_$1"
+    CC=$CC$ac_prog_cc_stdc_options
+    AC_MSG_RESULT([$ac_cv_prog_cc_$1]) ;;
+esac
+AS_IF([test "x$ac_cv_prog_cc_$1" != xno], [$5], [$6])
+])# _AC_C_STD_TRY
+
+# _AC_C_C99_TEST_HEADER
+# ---------------------
+# A C header suitable for testing for C99.
+AC_DEFUN([_AC_C_C99_TEST_HEADER],
+[[#include <stdarg.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <wchar.h>
+#include <stdio.h>
+
+// Check varargs macros.  These examples are taken from C99 6.10.3.5.
+#define debug(...) fprintf (stderr, __VA_ARGS__)
+#define showlist(...) puts (#__VA_ARGS__)
+#define report(test,...) ((test) ? puts (#test) : printf (__VA_ARGS__))
+static void
+test_varargs_macros (void)
+{
+  int x = 1234;
+  int y = 5678;
+  debug ("Flag");
+  debug ("X = %d\n", x);
+  showlist (The first, second, and third items.);
+  report (x>y, "x is %d but y is %d", x, y);
+}
+
+// Check long long types.
+#define BIG64 18446744073709551615ull
+#define BIG32 4294967295ul
+#define BIG_OK (BIG64 / BIG32 == 4294967297ull && BIG64 % BIG32 == 0)
+#if !BIG_OK
+  your preprocessor is broken;
+#endif
+#if BIG_OK
+#else
+  your preprocessor is broken;
+#endif
+static long long int bignum = -9223372036854775807LL;
+static unsigned long long int ubignum = BIG64;
+
+struct incomplete_array
+{
+  int datasize;
+  double data[];
+};
+
+struct named_init {
+  int number;
+  const wchar_t *name;
+  double average;
+};
+
+typedef const char *ccp;
+
+static inline int
+test_restrict (ccp restrict text)
+{
+  // See if C++-style comments work.
+  // Iterate through items via the restricted pointer.
+  // Also check for declarations in for loops.
+  for (unsigned int i = 0; *(text+i) != '\0'; ++i)
+    continue;
+  return 0;
+}
+
+// Check varargs and va_copy.
+static bool
+test_varargs (const char *format, ...)
+{
+  va_list args;
+  va_start (args, format);
+  va_list args_copy;
+  va_copy (args_copy, args);
+
+  const char *str = "";
+  int number = 0;
+  float fnumber = 0;
+
+  while (*format)
+    {
+      switch (*format++)
+        {
+        case 's': // string
+          str = va_arg (args_copy, const char *);
+          break;
+        case 'd': // int
+          number = va_arg (args_copy, int);
+          break;
+        case 'f': // float
+          fnumber = va_arg (args_copy, double);
+          break;
+        default:
+          break;
+        }
+    }
+  va_end (args_copy);
+  va_end (args);
+
+  return *str && number && fnumber;
+}]])# _AC_C_C99_TEST_HEADER
+
+# _AC_C_C99_TEST_BODY
+# -------------------
+# A C body suitable for testing for C99, assuming the corresponding header.
+AC_DEFUN([_AC_C_C99_TEST_BODY],
+[[
+  // Check bool.
+  _Bool success = false;
+
+  // Check restrict.
+  if (test_restrict ("String literal") == 0)
+    success = true;
+  char *restrict newvar = "Another string";
+
+  // Check varargs.
+  success &= test_varargs ("s, d' f .", "string", 65, 34.234);
+  test_varargs_macros ();
+
+  // Check flexible array members.
+  struct incomplete_array *ia =
+    malloc (sizeof (struct incomplete_array) + (sizeof (double) * 10));
+  ia->datasize = 10;
+  for (int i = 0; i < ia->datasize; ++i)
+    ia->data[i] = i * 1.234;
+
+  // Check named initializers.
+  struct named_init ni = {
+    .number = 34,
+    .name = L"Test wide string",
+    .average = 543.34343,
+  };
+
+  ni.number = 58;
+
+  int dynamic_array[ni.number];
+  dynamic_array[ni.number - 1] = 543;
+
+  // work around unused variable warnings
+  return (!success || bignum == 0LL || ubignum == 0uLL || newvar[0] == 'x'
+          || dynamic_array[ni.number - 1] != 543);
+]])
+
+# _AC_PROG_CC_C99 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
+# ----------------------------------------------------------------
+# If the C compiler is not in ISO C99 mode by default, try to add an
+# option to output variable CC to make it so.  This macro tries
+# various options that select ISO C99 on some system or another.  It
+# considers the compiler to be in ISO C99 mode if it handles _Bool,
+# // comments, flexible array members, inline, long long int, mixed
+# code and declarations, named initialization of structs, restrict,
+# va_copy, varargs macros, variable declarations in for loops and
+# variable length arrays.
+AC_DEFUN([_AC_PROG_CC_C99],
+[_AC_C_STD_TRY([c99],
+[_AC_C_C99_TEST_HEADER],
+[_AC_C_C99_TEST_BODY],
+dnl Try
+dnl GCC         -std=gnu99 (unused restrictive modes: -std=c99 -std=iso9899:1999)
+dnl IBM XL C    -qlanglvl=extc1x (V12.1; does not pass C11 test)
+dnl IBM XL C    -qlanglvl=extc99
+dnl             (pre-V12.1; unused restrictive mode: -qlanglvl=stdc99)
+dnl HP cc       -AC99
+dnl Intel ICC   -std=c99, -c99 (deprecated)
+dnl IRIX        -c99
+dnl Solaris     -D_STDC_C99=
+dnl             cc's -xc99 option uses linker magic to define the external
+dnl             symbol __xpg4 as if by "int __xpg4 = 1;", which enables C99
+dnl             behavior for C library functions.  This is not wanted here,
+dnl             because it means that a single module compiled with -xc99
+dnl             alters C runtime behavior for the entire program, not for
+dnl             just the module.  Instead, define the (private) symbol
+dnl             _STDC_C99, which suppresses a bogus failure in <stdbool.h>.
+dnl             The resulting compiler passes the test case here, and that's
+dnl             good enough.  For more, please see the thread starting at:
+dnl            https://lists.gnu.org/r/autoconf/2010-12/msg00059.html
+dnl Tru64       -c99
+dnl with extended modes being tried first.
+[[-std=gnu99 -std=c99 -c99 -AC99 -D_STDC_C99= -qlanglvl=extc1x -qlanglvl=extc99]], [$1], [$2])[]dnl
+])# _AC_PROG_CC_C99
+
+
+# _AC_PROG_CC_C11 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
+# ----------------------------------------------------------------
+# If the C compiler is not in ISO C11 mode by default, try to add an
+# option to output variable CC to make it so.  This macro tries
+# various options that select ISO C11 on some system or another.  It
+# considers the compiler to be in ISO C11 mode if it handles _Alignas,
+# _Alignof, _Noreturn, _Static_assert, UTF-8 string literals,
+# duplicate typedefs, and anonymous structures and unions.
+AC_DEFUN([_AC_PROG_CC_C11],
+[_AC_C_STD_TRY([c11],
+[_AC_C_C99_TEST_HEADER[
+// Check _Alignas.
+char _Alignas (double) aligned_as_double;
+char _Alignas (0) no_special_alignment;
+extern char aligned_as_int;
+char _Alignas (0) _Alignas (int) aligned_as_int;
+
+// Check _Alignof.
+enum
+{
+  int_alignment = _Alignof (int),
+  int_array_alignment = _Alignof (int[100]),
+  char_alignment = _Alignof (char)
+};
+_Static_assert (0 < -_Alignof (int), "_Alignof is signed");
+
+// Check _Noreturn.
+int _Noreturn does_not_return (void) { for (;;) continue; }
+
+// Check _Static_assert.
+struct test_static_assert
+{
+  int x;
+  _Static_assert (sizeof (int) <= sizeof (long int),
+                  "_Static_assert does not work in struct");
+  long int y;
+};
+
+// Check UTF-8 literals.
+#define u8 syntax error!
+char const utf8_literal[] = u8"happens to be ASCII" "another string";
+
+// Check duplicate typedefs.
+typedef long *long_ptr;
+typedef long int *long_ptr;
+typedef long_ptr long_ptr;
+
+// Anonymous structures and unions -- taken from C11 6.7.2.1 Example 1.
+struct anonymous
+{
+  union {
+    struct { int i; int j; };
+    struct { int k; long int l; } w;
+  };
+  int m;
+} v1;
+]],
+[_AC_C_C99_TEST_BODY[
+  v1.i = 2;
+  v1.w.k = 5;
+  _Static_assert ((offsetof (struct anonymous, i)
+                   == offsetof (struct anonymous, w.k)),
+                  "Anonymous union alignment botch");
+]],
+dnl Try
+dnl GCC         -std=gnu11 (unused restrictive mode: -std=c11)
+dnl with extended modes being tried first.
+dnl
+dnl Do not try -qlanglvl=extc1x, because IBM XL C V12.1 (the latest version as
+dnl of September 2012) does not pass the C11 test.  For now, try extc1x when
+dnl compiling the C99 test instead, since it enables _Static_assert and
+dnl _Noreturn, which is a win.  If -qlanglvl=extc11 or -qlanglvl=extc1x passes
+dnl the C11 test in some future version of IBM XL C, we'll add it here,
+dnl preferably extc11.
+[[-std=gnu11]], [$1], [$2])[]dnl
+])# _AC_PROG_CC_C11
+
+
+# AC_PROG_CC_C89
+# --------------
+# Do not use AU_ALIAS here and in AC_PROG_CC_C99 and AC_PROG_CC_STDC,
+# as that'd be incompatible with how Automake redefines AC_PROG_CC.  See
+# <https://lists.gnu.org/r/autoconf/2012-10/msg00048.html>.
+AU_DEFUN([AC_PROG_CC_C89],
+  [AC_REQUIRE([AC_PROG_CC])],
+  [$0 is obsolete; use AC_PROG_CC]
+)
+
+# AC_PROG_CC_C99
+# --------------
+AU_DEFUN([AC_PROG_CC_C99],
+  [AC_REQUIRE([AC_PROG_CC])],
+  [$0 is obsolete; use AC_PROG_CC]
+)
+
+# AC_PROG_CC_STDC
+# ---------------
+AU_DEFUN([AC_PROG_CC_STDC],
+  [AC_REQUIRE([AC_PROG_CC])],
+  [$0 is obsolete; use AC_PROG_CC]
+)
+
+
+# AC_C_PROTOTYPES
+# ---------------
+# Check if the C compiler supports prototypes, included if it needs
+# options.
+AC_DEFUN([AC_C_PROTOTYPES],
+[AC_REQUIRE([AC_PROG_CC])dnl
+if test "$ac_prog_cc_stdc" != no; then
+  AC_DEFINE(PROTOTYPES, 1,
+            [Define to 1 if the C compiler supports function prototypes.])
+  AC_DEFINE(__PROTOTYPES, 1,
+            [Define like PROTOTYPES; this can be used by system headers.])
+fi
+])# AC_C_PROTOTYPES
+
+
+# _AC_CXX_STD_TRY(STANDARD, TEST-PROLOGUE, TEST-BODY, OPTION-LIST,
+#                 ACTION-IF-AVAILABLE, ACTION-IF-UNAVAILABLE)
+# ----------------------------------------------------------------
+# Check whether the C++ compiler accepts features of STANDARD (e.g
+# `cxx98', `cxx11') by trying to compile a program of TEST-PROLOGUE
+# and TEST-BODY.  If this fails, try again with each compiler option
+# in the space-separated OPTION-LIST; if one helps, append it to CXX.
+# If eventually successful, run ACTION-IF-AVAILABLE, else
+# ACTION-IF-UNAVAILABLE.
+AC_DEFUN([_AC_CXX_STD_TRY],
+[AC_MSG_CHECKING([for $CXX option to enable ]m4_translit(m4_translit($1, [x], [+]), [a-z], [A-Z])[ features])
+AC_LANG_PUSH(C++)dnl
+AC_CACHE_VAL(ac_cv_prog_cxx_$1,
+[ac_cv_prog_cxx_$1=no
+ac_save_CXX=$CXX
+AC_LANG_CONFTEST([AC_LANG_PROGRAM([$2], [$3])])
+for ac_arg in '' $4
+do
+  CXX="$ac_save_CXX $ac_arg"
+  _AC_COMPILE_IFELSE([], [ac_cv_prog_cxx_$1=$ac_arg])
+  test "x$ac_cv_prog_cxx_$1" != "xno" && break
+done
+rm -f conftest.$ac_ext
+CXX=$ac_save_CXX
+])# AC_CACHE_VAL
+ac_prog_cxx_stdcxx_options=
+case "x$ac_cv_prog_cxx_$1" in
+  x)
+    AC_MSG_RESULT([none needed]) ;;
+  xno)
+    AC_MSG_RESULT([unsupported]) ;;
+  *)
+    ac_prog_cxx_stdcxx_options=" $ac_cv_prog_cxx_$1"
+    CXX=$CXX$ac_prog_cxx_stdcxx_options
+    AC_MSG_RESULT([$ac_cv_prog_cxx_$1]) ;;
+esac
+AC_LANG_POP(C++)dnl
+AS_IF([test "x$ac_cv_prog_cxx_$1" != xno], [$5], [$6])
+])# _AC_CXX_STD_TRY
+
+# _AC_CXX_CXX98_TEST_HEADER
+# -------------------------
+# A C++ header suitable for testing for CXX98.
+AC_DEFUN([_AC_CXX_CXX98_TEST_HEADER],
+[[
+#include <algorithm>
+#include <cstdlib>
+#include <fstream>
+#include <iomanip>
+#include <iostream>
+#include <list>
+#include <map>
+#include <set>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace test {
+  typedef std::vector<std::string> string_vec;
+  typedef std::pair<int,bool> map_value;
+  typedef std::map<std::string,map_value> map_type;
+  typedef std::set<int> set_type;
+
+  template<typename T>
+  class printer {
+  public:
+    printer(std::ostringstream& os): os(os) {}
+    void operator() (T elem) { os << elem << std::endl; }
+  private:
+    std::ostringstream& os;
+  };
+}
+]])# _AC_CXX_CXX98_TEST_HEADER
+
+# _AC_CXX_CXX98_TEST_BODY
+# -----------------------
+# A C++ body suitable for testing for CXX98, assuming the corresponding header.
+AC_DEFUN([_AC_CXX_CXX98_TEST_BODY],
+[[
+
+try {
+  // Basic string.
+  std::string teststr("ASCII text");
+  teststr += " string";
+
+  // Simple vector.
+  test::string_vec testvec;
+  testvec.push_back(teststr);
+  testvec.push_back("foo");
+  testvec.push_back("bar");
+  if (testvec.size() != 3) {
+    throw std::runtime_error("vector size is not 1");
+  }
+
+  // Dump vector into stringstream and obtain string.
+  std::ostringstream os;
+  for (test::string_vec::const_iterator i = testvec.begin();
+       i != testvec.end(); ++i) {
+    if (i + 1 != testvec.end()) {
+      os << teststr << '\n';
+    }
+  }
+  // Check algorithms work.
+  std::for_each(testvec.begin(), testvec.end(), test::printer<std::string>(os));
+  std::string os_out = os.str();
+
+  // Test pair and map.
+  test::map_type testmap;
+  testmap.insert(std::make_pair(std::string("key"),
+                                std::make_pair(53,false)));
+
+  // Test set.
+  int values[] = {9, 7, 13, 15, 4, 18, 12, 10, 5, 3, 14, 19, 17, 8, 6, 20, 16, 2, 11, 1};
+  test::set_type testset(values, values + sizeof(values)/sizeof(values[0]));
+  std::list<int> testlist(testset.begin(), testset.end());
+  std::copy(testset.begin(), testset.end(), std::back_inserter(testlist));
+} catch (const std::exception& e) {
+  std::cerr << "Caught exception: " << e.what() << std::endl;
+
+  // Test fstream
+  std::ofstream of("test.txt");
+  of << "Test ASCII text\n" << std::flush;
+  of << "N= " << std::hex << std::setw(8) << std::left << 534 << std::endl;
+  of.close();
+}
+std::exit(0);
+]])
+
+# _AC_CXX_CXX11_TEST_HEADER
+# -------------------------
+# A C++ header suitable for testing for CXX11.
+AC_DEFUN([_AC_CXX_CXX11_TEST_HEADER],
+[[
+#include <deque>
+#include <functional>
+#include <memory>
+#include <tuple>
+#include <array>
+#include <regex>
+#include <iostream>
+
+namespace cxx11test
+{
+  typedef std::shared_ptr<std::string> sptr;
+  typedef std::weak_ptr<std::string> wptr;
+
+  typedef std::tuple<std::string,int,double> tp;
+  typedef std::array<int, 20> int_array;
+
+  constexpr int get_val() { return 20; }
+
+  struct testinit
+  {
+    int i;
+    double d;
+  };
+
+  class delegate  {
+  public:
+    delegate(int n) : n(n) {}
+    delegate(): delegate(2354) {}
+
+    virtual int getval() { return this->n; };
+  protected:
+    int n;
+  };
+
+  class overridden : public delegate {
+  public:
+    overridden(int n): delegate(n) {}
+    virtual int getval() override final { return this->n * 2; }
+  };
+
+  class nocopy {
+  public:
+    nocopy(int i): i(i) {}
+    nocopy() = default;
+    nocopy(const nocopy&) = delete;
+    nocopy & operator=(const nocopy&) = delete;
+  private:
+    int i;
+  };
+}
+]])# _AC_CXX_CXX11_TEST_HEADER
+
+# _AC_CXX_CXX11_TEST_BODY
+# -----------------------
+# A C++ body suitable for testing for CXX11, assuming the corresponding header.
+AC_DEFUN([_AC_CXX_CXX11_TEST_BODY],
+[[
+{
+  // Test auto and decltype
+  std::deque<int> d;
+  d.push_front(43);
+  d.push_front(484);
+  d.push_front(3);
+  d.push_front(844);
+  int total = 0;
+  for (auto i = d.begin(); i != d.end(); ++i) { total += *i; }
+
+  auto a1 = 6538;
+  auto a2 = 48573953.4;
+  auto a3 = "String literal";
+
+  decltype(a2) a4 = 34895.034;
+}
+{
+  // Test constexpr
+  short sa[cxx11test::get_val()] = { 0 };
+}
+{
+  // Test initializer lists
+  cxx11test::testinit il = { 4323, 435234.23544 };
+}
+{
+  // Test range-based for and lambda
+  cxx11test::int_array array = {9, 7, 13, 15, 4, 18, 12, 10, 5, 3, 14, 19, 17, 8, 6, 20, 16, 2, 11, 1};
+  for (int &x : array) { x += 23; }
+  std::for_each(array.begin(), array.end(), [](int v1){ std::cout << v1; });
+}
+{
+  using cxx11test::sptr;
+  using cxx11test::wptr;
+
+  sptr sp(new std::string("ASCII string"));
+  wptr wp(sp);
+  sptr sp2(wp);
+}
+{
+  cxx11test::tp tuple("test", 54, 45.53434);
+  double d = std::get<2>(tuple);
+  std::string s;
+  int i;
+  std::tie(s,i,d) = tuple;
+}
+{
+  static std::regex filename_regex("^_?([a-z0-9_.]+-)+[a-z0-9]+$");
+  std::string testmatch("Test if this string matches");
+  bool match = std::regex_search(testmatch, filename_regex);
+}
+{
+  cxx11test::int_array array = {9, 7, 13, 15, 4, 18, 12, 10, 5, 3, 14, 19, 17, 8, 6, 20, 16, 2, 11, 1};
+  cxx11test::int_array::size_type size = array.size();
+}
+{
+  // Test constructor delegation
+  cxx11test::delegate d1;
+  cxx11test::delegate d2();
+  cxx11test::delegate d3(45);
+}
+{
+  // Test override and final
+  cxx11test::overridden o1(55464);
+}
+{
+  // Test nullptr
+  char *c = nullptr;
+}
+{
+  // Test template brackets
+  std::vector<std::pair<int,char*>> v1;
+}
+{
+  // Unicode literals
+  char const *utf8 = u8"UTF-8 string \u2500";
+  char16_t const *utf16 = u"UTF-8 string \u2500";
+  char32_t const *utf32 = U"UTF-32 string \u2500";
+}
+]])
+
+# _AC_PROG_CXX_CXX98 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
+# -------------------------------------------------------------------
+
+# If the C++ compiler is not in ISO C++98 mode by default, try to add
+# an option to output variable CXX to make it so.  This macro tries
+# various options that select ISO C++98 on some system or another.  It
+# considers the compiler to be in ISO C++98 mode if it handles basic
+# features of the std namespace including: string, containers (list,
+# map, set, vector), streams (fstreams, iostreams, stringstreams,
+# iomanip), pair, exceptions and algorithms.
+
+
+AC_DEFUN([_AC_PROG_CXX_CXX98],
+[_AC_CXX_STD_TRY([cxx98],
+[_AC_CXX_CXX98_TEST_HEADER],
+[_AC_CXX_CXX98_TEST_BODY],
+dnl Try
+dnl GCC         -std=gnu++98 (unused restrictive mode: -std=c++98)
+dnl IBM XL C    -qlanglvl=extended
+dnl HP aC++     -AA
+dnl Intel ICC   -std=gnu++98
+dnl Solaris     N/A (default)
+dnl Tru64       N/A (default, but -std gnu could be used)
+dnl with extended modes being tried first.
+[[-std=gnu++98 -std=c++98 -qlanglvl=extended -AA]], [$1], [$2])[]dnl
+])# _AC_PROG_CXX_CXX98
+
+# _AC_PROG_CXX_CXX11 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
+# -------------------------------------------------------------------
+# If the C++ compiler is not in ISO CXX11 mode by default, try to add
+# an option to output variable CXX to make it so.  This macro tries
+# various options that select ISO C++11 on some system or another.  It
+# considers the compiler to be in ISO C++11 mode if it handles all the
+# tests from the C++98 checks, plus the following: Language features
+# (auto, constexpr, decltype, default/deleted constructors, delegate
+# constructors, final, initializer lists, lambda functions, nullptr,
+# override, range-based for loops, template brackets without spaces,
+# unicode literals) and library features (array, memory (shared_ptr,
+# weak_ptr), regex and tuple types).
+AC_DEFUN([_AC_PROG_CXX_CXX11],
+[_AC_CXX_STD_TRY([cxx11],
+[_AC_CXX_CXX11_TEST_HEADER
+_AC_CXX_CXX98_TEST_HEADER],
+[_AC_CXX_CXX11_TEST_BODY
+_AC_CXX_CXX98_TEST_BODY],
+dnl Try
+dnl GCC         -std=gnu++11 (unused restrictive mode: -std=c++11) [and 0x variants]
+dnl IBM XL C    -qlanglvl=extended0x
+dnl             (pre-V12.1; unused restrictive mode: -qlanglvl=stdcxx11)
+dnl HP aC++     -AA
+dnl Intel ICC   -std=c++11 -std=c++0x
+dnl Solaris     N/A (no support)
+dnl Tru64       N/A (no support)
+dnl with extended modes being tried first.
+[[-std=gnu++11 -std=c++11 -std=gnu++0x -std=c++0x -qlanglvl=extended0x -AA]], [$1], [$2])[]dnl
+])# _AC_PROG_CXX_CXX11
+
+
+])# m4_version_prereq
diff --git a/gl/m4/stdalign.m4 b/gl/m4/stdalign.m4
index 20be01aa..dc297175 100644
--- a/gl/m4/stdalign.m4
+++ b/gl/m4/stdalign.m4
@@ -1,6 +1,6 @@
-# Check for stdalign.h that conforms to C11.
+# Check for alignas and alignof that conform to C23.
 
-dnl Copyright 2011-2013 Free Software Foundation, Inc.
+dnl Copyright 2011-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -9,16 +9,23 @@ dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_STDALIGN_H],
 [
-  AC_CACHE_CHECK([for working stdalign.h],
+  AC_CACHE_CHECK([for alignas and alignof],
     [gl_cv_header_working_stdalign_h],
-    [AC_COMPILE_IFELSE(
+    [gl_save_CFLAGS=$CFLAGS
+     for gl_working in "yes, keywords" "yes, <stdalign.h> macros"; do
+      AS_CASE([$gl_working],
+        [*stdalign.h*], [CFLAGS="$gl_save_CFLAGS -DINCLUDE_STDALIGN_H"])
+      AC_COMPILE_IFELSE(
        [AC_LANG_PROGRAM(
-          [[#include <stdalign.h>
+          [[#include <stdint.h>
+            #ifdef INCLUDE_STDALIGN_H
+             #include <stdalign.h>
+            #endif
             #include <stddef.h>
 
             /* Test that alignof yields a result consistent with offsetof.
                This catches GCC bug 52023
-               <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>.  */
+               <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>.  */
             #ifdef __cplusplus
                template <class t> struct alignof_helper { char a; t b; };
             # define ao(type) offsetof (alignof_helper<type>, b)
@@ -29,25 +36,103 @@ AC_DEFUN([gl_STDALIGN_H],
             char test_long[ao (long int) % _Alignof (long int) == 0 ? 1 : -1];
             char test_alignof[alignof (double) == _Alignof (double) ? 1 : -1];
 
-            /* Test _Alignas only on platforms where gnulib can help.  */
+            /* Test alignas only on platforms where gnulib can help.  */
             #if \
                 ((defined __cplusplus && 201103 <= __cplusplus) \
-                 || __GNUC__ || __IBMC__ || __IBMCPP__ || __ICC \
-                 || 0x5110 <= __SUNPRO_C || 1300 <= _MSC_VER)
+                 || (__TINYC__ && defined __attribute__) \
+                 || (defined __APPLE__ && defined __MACH__ \
+                     ? 4 < __GNUC__ + (1 <= __GNUC_MINOR__) \
+                     : __GNUC__) \
+                 || (__ia64 && (61200 <= __HP_cc || 61200 <= __HP_aCC)) \
+                 || __ICC || 0x590 <= __SUNPRO_C || 0x0600 <= __xlC__ \
+                 || 1300 <= _MSC_VER)
               struct alignas_test { char c; char alignas (8) alignas_8; };
               char test_alignas[offsetof (struct alignas_test, alignas_8) == 8
                                 ? 1 : -1];
             #endif
           ]])],
-       [gl_cv_header_working_stdalign_h=yes],
-       [gl_cv_header_working_stdalign_h=no])])
+       [gl_cv_header_working_stdalign_h=$gl_working],
+       [gl_cv_header_working_stdalign_h=no])
+
+      CFLAGS=$gl_save_CFLAGS
+      test "$gl_cv_header_working_stdalign_h" != no && break
+     done])
+
+  GL_GENERATE_STDALIGN_H=false
+  AS_CASE([$gl_cv_header_working_stdalign_h],
+    [no],
+      [GL_GENERATE_STDALIGN_H=true],
+    [yes*keyword*],
+      [AC_DEFINE([HAVE_C_ALIGNASOF], [1],
+         [Define to 1 if the alignas and alignof keywords work.])])
 
-  if test $gl_cv_header_working_stdalign_h = yes; then
-    STDALIGN_H=''
-  else
-    STDALIGN_H='stdalign.h'
-  fi
+  AC_CHECK_HEADERS_ONCE([stdalign.h])
 
-  AC_SUBST([STDALIGN_H])
-  AM_CONDITIONAL([GL_GENERATE_STDALIGN_H], [test -n "$STDALIGN_H"])
+  dnl The "zz" puts this toward config.h's end, to avoid potential
+  dnl collisions with other definitions.
+  AH_VERBATIM([zzalignas],
+[#if !defined HAVE_C_ALIGNASOF && __cplusplus < 201103 && !defined alignof
+# if HAVE_STDALIGN_H
+#  include <stdalign.h>
+# else
+   /* Substitute.  Keep consistent with gnulib/lib/stdalign.in.h.  */
+#  ifndef _GL_STDALIGN_H
+#   define _GL_STDALIGN_H
+#   undef _Alignas
+#   undef _Alignof
+#   if (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 \
+        || (defined __GNUC__ && __GNUC__ < 4 + (__GNUC_MINOR__ < 9) \
+            && !defined __clang__) \
+        || (defined __clang__ && __clang_major__ < 8))
+#    ifdef __cplusplus
+#     if (201103 <= __cplusplus || defined _MSC_VER)
+#      define _Alignof(type) alignof (type)
+#     else
+       template <class __t> struct __alignof_helper { char __a; __t __b; };
+#      define _Alignof(type) offsetof (__alignof_helper<type>, __b)
+#      define _GL_STDALIGN_NEEDS_STDDEF 1
+#     endif
+#    else
+#     if (defined __GNUC__ && 4 <= __GNUC__) || defined __clang__
+#      define _Alignof(type) __builtin_offsetof (struct { char __a; type __b; }, __b)
+#     else
+#      define _Alignof(type) offsetof (struct { char __a; type __b; }, __b)
+#      define _GL_STDALIGN_NEEDS_STDDEF 1
+#     endif
+#    endif
+#   endif
+#   if ! (defined __cplusplus && (201103 <= __cplusplus || defined _MSC_VER))
+#    define alignof _Alignof
+#   endif
+#   define __alignof_is_defined 1
+#   if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112
+#    if defined __cplusplus && (201103 <= __cplusplus || defined _MSC_VER)
+#     define _Alignas(a) alignas (a)
+#    elif (!defined __attribute__ \
+           && ((defined __APPLE__ && defined __MACH__ \
+                ? 4 < __GNUC__ + (1 <= __GNUC_MINOR__) \
+                : __GNUC__ && !defined __ibmxl__) \
+               || (4 <= __clang_major__) \
+               || (__ia64 && (61200 <= __HP_cc || 61200 <= __HP_aCC)) \
+               || __ICC || 0x590 <= __SUNPRO_C || 0x0600 <= __xlC__))
+#     define _Alignas(a) __attribute__ ((__aligned__ (a)))
+#    elif 1300 <= _MSC_VER
+#     define _Alignas(a) __declspec (align (a))
+#    endif
+#   endif
+#   if ((defined _Alignas \
+         && !(defined __cplusplus && (201103 <= __cplusplus || defined _MSC_VER))) \
+        || (defined __STDC_VERSION__ && 201112 <= __STDC_VERSION__))
+#    define alignas _Alignas
+#   endif
+#   if (defined alignas \
+        || (defined __cplusplus && (201103 <= __cplusplus || defined _MSC_VER)))
+#    define __alignas_is_defined 1
+#   endif
+#   if _GL_STDALIGN_NEEDS_STDDEF
+#    include <stddef.h>
+#   endif
+#  endif /* _GL_STDALIGN_H */
+# endif
+#endif])
 ])
diff --git a/gl/m4/stdbool.m4 b/gl/m4/stdbool.m4
deleted file mode 100644
index 80d5559a..00000000
--- a/gl/m4/stdbool.m4
+++ /dev/null
@@ -1,100 +0,0 @@
-# Check for stdbool.h that conforms to C99.
-
-dnl Copyright (C) 2002-2006, 2009-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-#serial 5
-
-# Prepare for substituting <stdbool.h> if it is not supported.
-
-AC_DEFUN([AM_STDBOOL_H],
-[
-  AC_REQUIRE([AC_CHECK_HEADER_STDBOOL])
-
-  # Define two additional variables used in the Makefile substitution.
-
-  if test "$ac_cv_header_stdbool_h" = yes; then
-    STDBOOL_H=''
-  else
-    STDBOOL_H='stdbool.h'
-  fi
-  AC_SUBST([STDBOOL_H])
-  AM_CONDITIONAL([GL_GENERATE_STDBOOL_H], [test -n "$STDBOOL_H"])
-
-  if test "$ac_cv_type__Bool" = yes; then
-    HAVE__BOOL=1
-  else
-    HAVE__BOOL=0
-  fi
-  AC_SUBST([HAVE__BOOL])
-])
-
-# AM_STDBOOL_H will be renamed to gl_STDBOOL_H in the future.
-AC_DEFUN([gl_STDBOOL_H], [AM_STDBOOL_H])
-
-# This version of the macro is needed in autoconf <= 2.68.
-
-AC_DEFUN([AC_CHECK_HEADER_STDBOOL],
-  [AC_CACHE_CHECK([for stdbool.h that conforms to C99],
-     [ac_cv_header_stdbool_h],
-     [AC_COMPILE_IFELSE(
-        [AC_LANG_PROGRAM(
-           [[
-             #include <stdbool.h>
-             #ifndef bool
-              "error: bool is not defined"
-             #endif
-             #ifndef false
-              "error: false is not defined"
-             #endif
-             #if false
-              "error: false is not 0"
-             #endif
-             #ifndef true
-              "error: true is not defined"
-             #endif
-             #if true != 1
-              "error: true is not 1"
-             #endif
-             #ifndef __bool_true_false_are_defined
-              "error: __bool_true_false_are_defined is not defined"
-             #endif
-
-             struct s { _Bool s: 1; _Bool t; } s;
-
-             char a[true == 1 ? 1 : -1];
-             char b[false == 0 ? 1 : -1];
-             char c[__bool_true_false_are_defined == 1 ? 1 : -1];
-             char d[(bool) 0.5 == true ? 1 : -1];
-             /* See body of main program for 'e'.  */
-             char f[(_Bool) 0.0 == false ? 1 : -1];
-             char g[true];
-             char h[sizeof (_Bool)];
-             char i[sizeof s.t];
-             enum { j = false, k = true, l = false * true, m = true * 256 };
-             /* The following fails for
-                HP aC++/ANSI C B3910B A.05.55 [Dec 04 2003]. */
-             _Bool n[m];
-             char o[sizeof n == m * sizeof n[0] ? 1 : -1];
-             char p[-1 - (_Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1];
-             /* Catch a bug in an HP-UX C compiler.  See
-                http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
-                http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html
-              */
-             _Bool q = true;
-             _Bool *pq = &q;
-           ]],
-           [[
-             bool e = &s;
-             *pq |= q;
-             *pq |= ! q;
-             /* Refer to every declared value, to avoid compiler optimizations.  */
-             return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l
-                     + !m + !n + !o + !p + !q + !pq);
-           ]])],
-        [ac_cv_header_stdbool_h=yes],
-        [ac_cv_header_stdbool_h=no])])
-   AC_CHECK_TYPES([_Bool])
-])
diff --git a/gl/m4/stddef_h.m4 b/gl/m4/stddef_h.m4
index 5da8ab1e..a2322ebb 100644
--- a/gl/m4/stddef_h.m4
+++ b/gl/m4/stddef_h.m4
@@ -1,19 +1,61 @@
-dnl A placeholder for POSIX 2008 <stddef.h>, for platforms that have issues.
-# stddef_h.m4 serial 4
-dnl Copyright (C) 2009-2013 Free Software Foundation, Inc.
+# stddef_h.m4 serial 13
+dnl Copyright (C) 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-AC_DEFUN([gl_STDDEF_H],
+dnl A placeholder for <stddef.h>, for platforms that have issues.
+
+AC_DEFUN_ONCE([gl_STDDEF_H],
 [
   AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
   AC_REQUIRE([gt_TYPE_WCHAR_T])
-  STDDEF_H=
+
+  dnl Persuade OpenBSD <stddef.h> to declare max_align_t.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  GL_GENERATE_STDDEF_H=false
+
+  dnl Test whether the type max_align_t exists and whether its alignment
+  dnl "is as great as is supported by the implementation in all contexts".
+  AC_CACHE_CHECK([for good max_align_t],
+    [gl_cv_type_max_align_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[/* On FreeBSD 12.0/x86, max_align_t defined by <stddef.h> has
+               the correct alignment with the default (wrong) definition of
+               _Alignof, but a wrong alignment as soon as we activate an
+               ISO C compliant _Alignof definition.  */
+            #if ((defined __GNUC__ && 4 <= __GNUC__) || defined __clang__) && !defined __cplusplus
+             #define _Alignof(type) __builtin_offsetof (struct { char __a; type __b; }, __b)
+            #endif
+            #include <stddef.h>
+            unsigned int s = sizeof (max_align_t);
+            #if defined __GNUC__ || defined __clang__ || defined __IBM__ALIGNOF__
+            int check1[2 * (__alignof__ (double) <= __alignof__ (max_align_t)) - 1];
+            int check2[2 * (__alignof__ (long double) <= __alignof__ (max_align_t)) - 1];
+            #endif
+            typedef struct { char a; max_align_t b; } max_helper;
+            typedef struct { char a; long b; } long_helper;
+            typedef struct { char a; double b; } double_helper;
+            typedef struct { char a; long double b; } long_double_helper;
+            int check3[2 * (offsetof (long_helper, b) <= offsetof (max_helper, b)) - 1];
+            int check4[2 * (offsetof (double_helper, b) <= offsetof (max_helper, b)) - 1];
+            int check5[2 * (offsetof (long_double_helper, b) <= offsetof (max_helper, b)) - 1];
+          ]])],
+       [gl_cv_type_max_align_t=yes],
+       [gl_cv_type_max_align_t=no])
+    ])
+  if test $gl_cv_type_max_align_t = no; then
+    HAVE_MAX_ALIGN_T=0
+    GL_GENERATE_STDDEF_H=true
+  fi
+
   if test $gt_cv_c_wchar_t = no; then
     HAVE_WCHAR_T=0
-    STDDEF_H=stddef.h
+    GL_GENERATE_STDDEF_H=true
   fi
+
   AC_CACHE_CHECK([whether NULL can be used in arbitrary expressions],
     [gl_cv_decl_null_works],
     [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stddef.h>
@@ -23,25 +65,40 @@ AC_DEFUN([gl_STDDEF_H],
       [gl_cv_decl_null_works=no])])
   if test $gl_cv_decl_null_works = no; then
     REPLACE_NULL=1
-    STDDEF_H=stddef.h
+    GL_GENERATE_STDDEF_H=true
   fi
-  AC_SUBST([STDDEF_H])
-  AM_CONDITIONAL([GL_GENERATE_STDDEF_H], [test -n "$STDDEF_H"])
-  if test -n "$STDDEF_H"; then
+
+  if $GL_GENERATE_STDDEF_H; then
     gl_NEXT_HEADERS([stddef.h])
   fi
 ])
 
+# gl_STDDEF_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_STDDEF_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_STDDEF_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_STDDEF_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_STDDEF_H_MODULE_INDICATOR_DEFAULTS], [
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_STDDEF_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_STDDEF_H_DEFAULTS],
 [
   dnl Assume proper GNU behavior unless another module says otherwise.
   REPLACE_NULL=0;                AC_SUBST([REPLACE_NULL])
+  HAVE_MAX_ALIGN_T=1;            AC_SUBST([HAVE_MAX_ALIGN_T])
   HAVE_WCHAR_T=1;                AC_SUBST([HAVE_WCHAR_T])
 ])
diff --git a/gl/m4/stdint.m4 b/gl/m4/stdint.m4
index 27cdcdb9..d6961b09 100644
--- a/gl/m4/stdint.m4
+++ b/gl/m4/stdint.m4
@@ -1,5 +1,5 @@
-# stdint.m4 serial 43
-dnl Copyright (C) 2001-2013 Free Software Foundation, Inc.
+# stdint.m4 serial 61
+dnl Copyright (C) 2001-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -7,25 +7,22 @@ dnl with or without modifications, as long as this notice is preserved.
 dnl From Paul Eggert and Bruno Haible.
 dnl Test whether <stdint.h> is supported or must be substituted.
 
+AC_PREREQ([2.61])
+
 AC_DEFUN_ONCE([gl_STDINT_H],
 [
   AC_PREREQ([2.59])dnl
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
 
-  dnl Check for long long int and unsigned long long int.
-  AC_REQUIRE([AC_TYPE_LONG_LONG_INT])
-  if test $ac_cv_type_long_long_int = yes; then
-    HAVE_LONG_LONG_INT=1
-  else
-    HAVE_LONG_LONG_INT=0
-  fi
-  AC_SUBST([HAVE_LONG_LONG_INT])
-  AC_REQUIRE([AC_TYPE_UNSIGNED_LONG_LONG_INT])
-  if test $ac_cv_type_unsigned_long_long_int = yes; then
-    HAVE_UNSIGNED_LONG_LONG_INT=1
-  else
-    HAVE_UNSIGNED_LONG_LONG_INT=0
-  fi
-  AC_SUBST([HAVE_UNSIGNED_LONG_LONG_INT])
+  AC_REQUIRE([gl_LIMITS_H])
+  AC_REQUIRE([gt_TYPE_WINT_T])
+
+  dnl For backward compatibility. Some packages may still be testing these
+  dnl macros.
+  AC_DEFINE([HAVE_LONG_LONG_INT], [1],
+    [Define to 1 if the system has the type 'long long int'.])
+  AC_DEFINE([HAVE_UNSIGNED_LONG_LONG_INT], [1],
+    [Define to 1 if the system has the type 'unsigned long long int'.])
 
   dnl Check for <wchar.h>, in the same way as gl_WCHAR_H does.
   AC_CHECK_HEADERS_ONCE([wchar.h])
@@ -37,7 +34,7 @@ AC_DEFUN_ONCE([gl_STDINT_H],
   AC_SUBST([HAVE_WCHAR_H])
 
   dnl Check for <inttypes.h>.
-  dnl AC_INCLUDES_DEFAULT defines $ac_cv_header_inttypes_h.
+  AC_CHECK_HEADERS_ONCE([inttypes.h])
   if test $ac_cv_header_inttypes_h = yes; then
     HAVE_INTTYPES_H=1
   else
@@ -46,7 +43,7 @@ AC_DEFUN_ONCE([gl_STDINT_H],
   AC_SUBST([HAVE_INTTYPES_H])
 
   dnl Check for <sys/types.h>.
-  dnl AC_INCLUDES_DEFAULT defines $ac_cv_header_sys_types_h.
+  AC_CHECK_HEADERS_ONCE([sys/types.h])
   if test $ac_cv_header_sys_types_h = yes; then
     HAVE_SYS_TYPES_H=1
   else
@@ -70,6 +67,8 @@ AC_DEFUN_ONCE([gl_STDINT_H],
        AC_COMPILE_IFELSE([
          AC_LANG_PROGRAM([[
 #define _GL_JUST_INCLUDE_SYSTEM_STDINT_H 1 /* work if build isn't clean */
+#define __STDC_CONSTANT_MACROS 1
+#define __STDC_LIMIT_MACROS 1
 #include <stdint.h>
 /* Dragonfly defines WCHAR_MIN, WCHAR_MAX only in <wchar.h>.  */
 #if !(defined WCHAR_MIN && defined WCHAR_MAX)
@@ -150,6 +149,15 @@ uintptr_t h = UINTPTR_MAX;
 intmax_t i = INTMAX_MAX;
 uintmax_t j = UINTMAX_MAX;
 
+/* Check that SIZE_MAX has the correct type, if possible.  */
+#if 201112 <= __STDC_VERSION__
+int k = _Generic (SIZE_MAX, size_t: 0);
+#elif (2 <= __GNUC__ || 4 <= __clang_major__ || defined __IBM__TYPEOF__ \
+       || (0x5110 <= __SUNPRO_C && !__STDC__))
+extern size_t k;
+extern __typeof__ (SIZE_MAX) k;
+#endif
+
 #include <limits.h> /* for CHAR_BIT */
 #define TYPE_MINIMUM(t) \
   ((t) ((t) 0 < (t) -1 ? (t) 0 : ~ TYPE_MAXIMUM (t)))
@@ -162,7 +170,7 @@ struct s {
       PTRDIFF_MIN == TYPE_MINIMUM (ptrdiff_t)
       && PTRDIFF_MAX == TYPE_MAXIMUM (ptrdiff_t)
       ? 1 : -1;
-  /* Detect bug in FreeBSD 6.0 / ia64.  */
+  /* Detect bug in FreeBSD 6.0/ia64 and FreeBSD 13.0/arm64.  */
   int check_SIG_ATOMIC:
       SIG_ATOMIC_MIN == TYPE_MINIMUM (sig_atomic_t)
       && SIG_ATOMIC_MAX == TYPE_MAXIMUM (sig_atomic_t)
@@ -218,6 +226,8 @@ struct s {
           AC_RUN_IFELSE([
             AC_LANG_PROGRAM([[
 #define _GL_JUST_INCLUDE_SYSTEM_STDINT_H 1 /* work if build isn't clean */
+#define __STDC_CONSTANT_MACROS 1
+#define __STDC_LIMIT_MACROS 1
 #include <stdint.h>
 ]
 gl_STDINT_INCLUDES
@@ -272,36 +282,88 @@ static const char *macro_values[] =
 ]])],
               [gl_cv_header_working_stdint_h=yes],
               [],
-              [dnl When cross-compiling, assume it works.
-               gl_cv_header_working_stdint_h=yes
+              [case "$host_os" in
+                         # Guess yes on native Windows.
+                 mingw*) gl_cv_header_working_stdint_h="guessing yes" ;;
+                         # In general, assume it works.
+                 *)      gl_cv_header_working_stdint_h="guessing yes" ;;
+               esac
               ])
          ])
       ])
   fi
-  if test "$gl_cv_header_working_stdint_h" = yes; then
-    STDINT_H=
-  else
-    dnl Check for <sys/inttypes.h>, and for
-    dnl <sys/bitypes.h> (used in Linux libc4 >= 4.6.7 and libc5).
-    AC_CHECK_HEADERS([sys/inttypes.h sys/bitypes.h])
-    if test $ac_cv_header_sys_inttypes_h = yes; then
-      HAVE_SYS_INTTYPES_H=1
-    else
-      HAVE_SYS_INTTYPES_H=0
-    fi
-    AC_SUBST([HAVE_SYS_INTTYPES_H])
-    if test $ac_cv_header_sys_bitypes_h = yes; then
-      HAVE_SYS_BITYPES_H=1
-    else
-      HAVE_SYS_BITYPES_H=0
-    fi
-    AC_SUBST([HAVE_SYS_BITYPES_H])
 
-    gl_STDINT_TYPE_PROPERTIES
-    STDINT_H=stdint.h
-  fi
-  AC_SUBST([STDINT_H])
-  AM_CONDITIONAL([GL_GENERATE_STDINT_H], [test -n "$STDINT_H"])
+  HAVE_C99_STDINT_H=0
+  HAVE_SYS_BITYPES_H=0
+  HAVE_SYS_INTTYPES_H=0
+  GL_GENERATE_STDINT_H=true
+  case "$gl_cv_header_working_stdint_h" in
+    *yes)
+      HAVE_C99_STDINT_H=1
+      dnl Now see whether the system <stdint.h> works without
+      dnl __STDC_CONSTANT_MACROS/__STDC_LIMIT_MACROS defined.
+      dnl If not, there would be problems when stdint.h is included from C++.
+      AC_CACHE_CHECK([whether stdint.h works without ISO C predefines],
+        [gl_cv_header_stdint_without_STDC_macros],
+        [gl_cv_header_stdint_without_STDC_macros=no
+         AC_COMPILE_IFELSE([
+           AC_LANG_PROGRAM([[
+#define _GL_JUST_INCLUDE_SYSTEM_STDINT_H 1 /* work if build isn't clean */
+#include <stdint.h>
+]
+gl_STDINT_INCLUDES
+[
+intmax_t im = INTMAX_MAX;
+int32_t i32 = INT32_C (0x7fffffff);
+           ]])],
+           [gl_cv_header_stdint_without_STDC_macros=yes])
+        ])
+
+      if test $gl_cv_header_stdint_without_STDC_macros = no; then
+        AC_DEFINE([__STDC_CONSTANT_MACROS], [1],
+          [Define to 1 if the system <stdint.h> predates C++11.])
+        AC_DEFINE([__STDC_LIMIT_MACROS], [1],
+          [Define to 1 if the system <stdint.h> predates C++11.])
+      fi
+      AC_CACHE_CHECK([whether stdint.h has UINTMAX_WIDTH etc.],
+        [gl_cv_header_stdint_width],
+        [gl_cv_header_stdint_width=no
+         AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM([[
+              /* Work if build is not clean.  */
+              #define _GL_JUST_INCLUDE_SYSTEM_STDINT_H 1
+              #ifndef __STDC_WANT_IEC_60559_BFP_EXT__
+               #define __STDC_WANT_IEC_60559_BFP_EXT__ 1
+              #endif
+              #include <stdint.h>
+              ]gl_STDINT_INCLUDES[
+              int iw = UINTMAX_WIDTH;
+              ]])],
+           [gl_cv_header_stdint_width=yes])])
+      if test "$gl_cv_header_stdint_width" = yes; then
+        GL_GENERATE_STDINT_H=false
+      fi
+      ;;
+    *)
+      dnl Check for <sys/inttypes.h>, and for
+      dnl <sys/bitypes.h> (used in Linux libc4 >= 4.6.7 and libc5).
+      AC_CHECK_HEADERS([sys/inttypes.h sys/bitypes.h])
+      if test $ac_cv_header_sys_inttypes_h = yes; then
+        HAVE_SYS_INTTYPES_H=1
+      fi
+      if test $ac_cv_header_sys_bitypes_h = yes; then
+        HAVE_SYS_BITYPES_H=1
+      fi
+      gl_STDINT_TYPE_PROPERTIES
+      ;;
+  esac
+
+  dnl The substitute stdint.h needs the substitute limit.h's _GL_INTEGER_WIDTH.
+  gl_REPLACE_LIMITS_H
+
+  AC_SUBST([HAVE_C99_STDINT_H])
+  AC_SUBST([HAVE_SYS_BITYPES_H])
+  AC_SUBST([HAVE_SYS_INTTYPES_H])
 ])
 
 dnl gl_STDINT_BITSIZEOF(TYPES, INCLUDES)
@@ -429,13 +491,9 @@ AC_DEFUN([gl_INTEGER_TYPE_SUFFIX],
 dnl gl_STDINT_INCLUDES
 AC_DEFUN([gl_STDINT_INCLUDES],
 [[
-  /* BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-     included before <wchar.h>.  */
   #include <stddef.h>
   #include <signal.h>
   #if HAVE_WCHAR_H
-  # include <stdio.h>
-  # include <time.h>
   # include <wchar.h>
   #endif
 ]])
@@ -467,18 +525,7 @@ AC_DEFUN([gl_STDINT_TYPE_PROPERTIES],
   dnl requirement that wint_t is "unchanged by default argument promotions".
   dnl In this case gnulib's <wchar.h> and <wctype.h> override wint_t.
   dnl Set the variable BITSIZEOF_WINT_T accordingly.
-  if test $BITSIZEOF_WINT_T -lt 32; then
+  if test $GNULIBHEADERS_OVERRIDE_WINT_T = 1; then
     BITSIZEOF_WINT_T=32
   fi
 ])
-
-dnl Autoconf >= 2.61 has AC_COMPUTE_INT built-in.
-dnl Remove this when we can assume autoconf >= 2.61.
-m4_ifdef([AC_COMPUTE_INT], [], [
-  AC_DEFUN([AC_COMPUTE_INT], [_AC_COMPUTE_INT([$2],[$1],[$3],[$4])])
-])
-
-# Hey Emacs!
-# Local Variables:
-# indent-tabs-mode: nil
-# End:
diff --git a/gl/m4/stdint_h.m4 b/gl/m4/stdint_h.m4
index 511ab4e9..70349f6c 100644
--- a/gl/m4/stdint_h.m4
+++ b/gl/m4/stdint_h.m4
@@ -1,5 +1,5 @@
 # stdint_h.m4 serial 9
-dnl Copyright (C) 1997-2004, 2006, 2008-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 1997-2004, 2006, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/stdio_h.m4 b/gl/m4/stdio_h.m4
index ebade067..94271e11 100644
--- a/gl/m4/stdio_h.m4
+++ b/gl/m4/stdio_h.m4
@@ -1,72 +1,71 @@
-# stdio_h.m4 serial 43
-dnl Copyright (C) 2007-2013 Free Software Foundation, Inc.
+# stdio_h.m4 serial 59
+dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-AC_DEFUN([gl_STDIO_H],
+AC_DEFUN_ONCE([gl_STDIO_H],
 [
   AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AH_VERBATIM([MINGW_ANSI_STDIO],
+[/* Use GNU style printf and scanf.  */
+#ifndef __USE_MINGW_ANSI_STDIO
+# undef __USE_MINGW_ANSI_STDIO
+#endif
+])
+  AC_DEFINE([__USE_MINGW_ANSI_STDIO])
   gl_NEXT_HEADERS([stdio.h])
 
-  dnl No need to create extra modules for these functions. Everyone who uses
-  dnl <stdio.h> likely needs them.
-  GNULIB_FSCANF=1
-  gl_MODULE_INDICATOR([fscanf])
-  GNULIB_SCANF=1
-  gl_MODULE_INDICATOR([scanf])
-  GNULIB_FGETC=1
-  GNULIB_GETC=1
-  GNULIB_GETCHAR=1
-  GNULIB_FGETS=1
-  GNULIB_FREAD=1
-  dnl This ifdef is necessary to avoid an error "missing file lib/stdio-read.c"
-  dnl "expected source file, required through AC_LIBSOURCES, not found". It is
-  dnl also an optimization, to avoid performing a configure check whose result
-  dnl is not used. But it does not make the test of GNULIB_STDIO_H_NONBLOCKING
-  dnl or GNULIB_NONBLOCKING redundant.
+  dnl Determine whether __USE_MINGW_ANSI_STDIO makes printf and
+  dnl inttypes.h behave like gnu instead of system; we must give our
+  dnl printf wrapper the right attribute to match.
+  AC_CACHE_CHECK([which flavor of printf attribute matches inttypes macros],
+    [gl_cv_func_printf_attribute_flavor],
+    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+       #define __STDC_FORMAT_MACROS 1
+       #include <stdio.h>
+       #include <inttypes.h>
+       /* For non-mingw systems, compilation will trivially succeed.
+          For mingw, compilation will succeed for older mingw (system
+          printf, "I64d") and fail for newer mingw (gnu printf, "lld"). */
+       #if (defined _WIN32 && ! defined __CYGWIN__) && \
+         (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
+       extern char PRIdMAX_probe[sizeof PRIdMAX == sizeof "I64d" ? 1 : -1];
+       #endif
+      ]])], [gl_cv_func_printf_attribute_flavor=system],
+      [gl_cv_func_printf_attribute_flavor=gnu])])
+  if test "$gl_cv_func_printf_attribute_flavor" = gnu; then
+    AC_DEFINE([GNULIB_PRINTF_ATTRIBUTE_FLAVOR_GNU], [1],
+      [Define to 1 if printf and friends should be labeled with
+       attribute "__gnu_printf__" instead of "__printf__"])
+  fi
+
+  dnl This ifdef is an optimization, to avoid performing a configure check whose
+  dnl result is not used. But it does not make the test of
+  dnl GNULIB_STDIO_H_NONBLOCKING or GNULIB_NONBLOCKING redundant.
   m4_ifdef([gl_NONBLOCKING_IO], [
     gl_NONBLOCKING_IO
     if test $gl_cv_have_nonblocking != yes; then
       REPLACE_STDIO_READ_FUNCS=1
-      AC_LIBOBJ([stdio-read])
     fi
   ])
 
-  dnl No need to create extra modules for these functions. Everyone who uses
-  dnl <stdio.h> likely needs them.
-  GNULIB_FPRINTF=1
-  GNULIB_PRINTF=1
-  GNULIB_VFPRINTF=1
-  GNULIB_VPRINTF=1
-  GNULIB_FPUTC=1
-  GNULIB_PUTC=1
-  GNULIB_PUTCHAR=1
-  GNULIB_FPUTS=1
-  GNULIB_PUTS=1
-  GNULIB_FWRITE=1
-  dnl This ifdef is necessary to avoid an error "missing file lib/stdio-write.c"
-  dnl "expected source file, required through AC_LIBSOURCES, not found". It is
-  dnl also an optimization, to avoid performing a configure check whose result
-  dnl is not used. But it does not make the test of GNULIB_STDIO_H_SIGPIPE or
-  dnl GNULIB_SIGPIPE redundant.
+  dnl This ifdef is an optimization, to avoid performing a configure check whose
+  dnl result is not used. But it does not make the test of
+  dnl GNULIB_STDIO_H_SIGPIPE or GNULIB_SIGPIPE redundant.
   m4_ifdef([gl_SIGNAL_SIGPIPE], [
     gl_SIGNAL_SIGPIPE
     if test $gl_cv_header_signal_h_SIGPIPE != yes; then
       REPLACE_STDIO_WRITE_FUNCS=1
-      AC_LIBOBJ([stdio-write])
     fi
   ])
-  dnl This ifdef is necessary to avoid an error "missing file lib/stdio-write.c"
-  dnl "expected source file, required through AC_LIBSOURCES, not found". It is
-  dnl also an optimization, to avoid performing a configure check whose result
-  dnl is not used. But it does not make the test of GNULIB_STDIO_H_NONBLOCKING
-  dnl or GNULIB_NONBLOCKING redundant.
+  dnl This ifdef is an optimization, to avoid performing a configure check whose
+  dnl result is not used. But it does not make the test of
+  dnl GNULIB_STDIO_H_NONBLOCKING or GNULIB_NONBLOCKING redundant.
   m4_ifdef([gl_NONBLOCKING_IO], [
     gl_NONBLOCKING_IO
     if test $gl_cv_have_nonblocking != yes; then
       REPLACE_STDIO_WRITE_FUNCS=1
-      AC_LIBOBJ([stdio-write])
     fi
   ])
 
@@ -76,73 +75,104 @@ AC_DEFUN([gl_STDIO_H],
   gl_WARN_ON_USE_PREPARE([[#include <stdio.h>
     ]], [dprintf fpurge fseeko ftello getdelim getline gets pclose popen
     renameat snprintf tmpfile vdprintf vsnprintf])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_CHECK_DECLS_ONCE([fcloseall])
+  if test $ac_cv_have_decl_fcloseall = no; then
+    HAVE_DECL_FCLOSEALL=0
+  fi
 ])
 
+# gl_STDIO_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_STDIO_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_STDIO_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_STDIO_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_STDIO_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_DPRINTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FCLOSE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FDOPEN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FFLUSH])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FGETC])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FGETS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FOPEN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FOPEN_GNU])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FPRINTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FPRINTF_POSIX])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FPURGE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FPUTC])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FPUTS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FREAD])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FREOPEN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FSCANF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FSEEK])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FSEEKO])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FTELL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FTELLO])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FWRITE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETC])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETCHAR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETDELIM])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETLINE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_OBSTACK_PRINTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_OBSTACK_PRINTF_POSIX])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PCLOSE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PERROR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_POPEN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PRINTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PRINTF_POSIX])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PUTC])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PUTCHAR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PUTS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_REMOVE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RENAME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RENAMEAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SCANF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SNPRINTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SPRINTF_POSIX])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STDIO_H_NONBLOCKING])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STDIO_H_SIGPIPE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TMPFILE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_VASPRINTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_VFSCANF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_VSCANF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_VDPRINTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_VFPRINTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_VFPRINTF_POSIX])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_VPRINTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_VPRINTF_POSIX])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_VSNPRINTF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_VSPRINTF_POSIX])
+    dnl Support Microsoft deprecated alias function names by default.
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_FCLOSEALL], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_FDOPEN], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_FILENO], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_GETW], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_PUTW], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_TEMPNAM], [1])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_STDIO_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_STDIO_H_DEFAULTS],
 [
-  GNULIB_DPRINTF=0;              AC_SUBST([GNULIB_DPRINTF])
-  GNULIB_FCLOSE=0;               AC_SUBST([GNULIB_FCLOSE])
-  GNULIB_FDOPEN=0;               AC_SUBST([GNULIB_FDOPEN])
-  GNULIB_FFLUSH=0;               AC_SUBST([GNULIB_FFLUSH])
-  GNULIB_FGETC=0;                AC_SUBST([GNULIB_FGETC])
-  GNULIB_FGETS=0;                AC_SUBST([GNULIB_FGETS])
-  GNULIB_FOPEN=0;                AC_SUBST([GNULIB_FOPEN])
-  GNULIB_FPRINTF=0;              AC_SUBST([GNULIB_FPRINTF])
-  GNULIB_FPRINTF_POSIX=0;        AC_SUBST([GNULIB_FPRINTF_POSIX])
-  GNULIB_FPURGE=0;               AC_SUBST([GNULIB_FPURGE])
-  GNULIB_FPUTC=0;                AC_SUBST([GNULIB_FPUTC])
-  GNULIB_FPUTS=0;                AC_SUBST([GNULIB_FPUTS])
-  GNULIB_FREAD=0;                AC_SUBST([GNULIB_FREAD])
-  GNULIB_FREOPEN=0;              AC_SUBST([GNULIB_FREOPEN])
-  GNULIB_FSCANF=0;               AC_SUBST([GNULIB_FSCANF])
-  GNULIB_FSEEK=0;                AC_SUBST([GNULIB_FSEEK])
-  GNULIB_FSEEKO=0;               AC_SUBST([GNULIB_FSEEKO])
-  GNULIB_FTELL=0;                AC_SUBST([GNULIB_FTELL])
-  GNULIB_FTELLO=0;               AC_SUBST([GNULIB_FTELLO])
-  GNULIB_FWRITE=0;               AC_SUBST([GNULIB_FWRITE])
-  GNULIB_GETC=0;                 AC_SUBST([GNULIB_GETC])
-  GNULIB_GETCHAR=0;              AC_SUBST([GNULIB_GETCHAR])
-  GNULIB_GETDELIM=0;             AC_SUBST([GNULIB_GETDELIM])
-  GNULIB_GETLINE=0;              AC_SUBST([GNULIB_GETLINE])
-  GNULIB_OBSTACK_PRINTF=0;       AC_SUBST([GNULIB_OBSTACK_PRINTF])
-  GNULIB_OBSTACK_PRINTF_POSIX=0; AC_SUBST([GNULIB_OBSTACK_PRINTF_POSIX])
-  GNULIB_PCLOSE=0;               AC_SUBST([GNULIB_PCLOSE])
-  GNULIB_PERROR=0;               AC_SUBST([GNULIB_PERROR])
-  GNULIB_POPEN=0;                AC_SUBST([GNULIB_POPEN])
-  GNULIB_PRINTF=0;               AC_SUBST([GNULIB_PRINTF])
-  GNULIB_PRINTF_POSIX=0;         AC_SUBST([GNULIB_PRINTF_POSIX])
-  GNULIB_PUTC=0;                 AC_SUBST([GNULIB_PUTC])
-  GNULIB_PUTCHAR=0;              AC_SUBST([GNULIB_PUTCHAR])
-  GNULIB_PUTS=0;                 AC_SUBST([GNULIB_PUTS])
-  GNULIB_REMOVE=0;               AC_SUBST([GNULIB_REMOVE])
-  GNULIB_RENAME=0;               AC_SUBST([GNULIB_RENAME])
-  GNULIB_RENAMEAT=0;             AC_SUBST([GNULIB_RENAMEAT])
-  GNULIB_SCANF=0;                AC_SUBST([GNULIB_SCANF])
-  GNULIB_SNPRINTF=0;             AC_SUBST([GNULIB_SNPRINTF])
-  GNULIB_SPRINTF_POSIX=0;        AC_SUBST([GNULIB_SPRINTF_POSIX])
-  GNULIB_STDIO_H_NONBLOCKING=0;  AC_SUBST([GNULIB_STDIO_H_NONBLOCKING])
-  GNULIB_STDIO_H_SIGPIPE=0;      AC_SUBST([GNULIB_STDIO_H_SIGPIPE])
-  GNULIB_TMPFILE=0;              AC_SUBST([GNULIB_TMPFILE])
-  GNULIB_VASPRINTF=0;            AC_SUBST([GNULIB_VASPRINTF])
-  GNULIB_VFSCANF=0;              AC_SUBST([GNULIB_VFSCANF])
-  GNULIB_VSCANF=0;               AC_SUBST([GNULIB_VSCANF])
-  GNULIB_VDPRINTF=0;             AC_SUBST([GNULIB_VDPRINTF])
-  GNULIB_VFPRINTF=0;             AC_SUBST([GNULIB_VFPRINTF])
-  GNULIB_VFPRINTF_POSIX=0;       AC_SUBST([GNULIB_VFPRINTF_POSIX])
-  GNULIB_VPRINTF=0;              AC_SUBST([GNULIB_VPRINTF])
-  GNULIB_VPRINTF_POSIX=0;        AC_SUBST([GNULIB_VPRINTF_POSIX])
-  GNULIB_VSNPRINTF=0;            AC_SUBST([GNULIB_VSNPRINTF])
-  GNULIB_VSPRINTF_POSIX=0;       AC_SUBST([GNULIB_VSPRINTF_POSIX])
   dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_DECL_FCLOSEALL=1;         AC_SUBST([HAVE_DECL_FCLOSEALL])
   HAVE_DECL_FPURGE=1;            AC_SUBST([HAVE_DECL_FPURGE])
   HAVE_DECL_FSEEKO=1;            AC_SUBST([HAVE_DECL_FSEEKO])
   HAVE_DECL_FTELLO=1;            AC_SUBST([HAVE_DECL_FTELLO])
@@ -164,6 +194,7 @@ AC_DEFUN([gl_STDIO_H_DEFAULTS],
   REPLACE_FDOPEN=0;              AC_SUBST([REPLACE_FDOPEN])
   REPLACE_FFLUSH=0;              AC_SUBST([REPLACE_FFLUSH])
   REPLACE_FOPEN=0;               AC_SUBST([REPLACE_FOPEN])
+  REPLACE_FOPEN_FOR_FOPEN_GNU=0; AC_SUBST([REPLACE_FOPEN_FOR_FOPEN_GNU])
   REPLACE_FPRINTF=0;             AC_SUBST([REPLACE_FPRINTF])
   REPLACE_FPURGE=0;              AC_SUBST([REPLACE_FPURGE])
   REPLACE_FREOPEN=0;             AC_SUBST([REPLACE_FREOPEN])
diff --git a/gl/m4/stdlib_h.m4 b/gl/m4/stdlib_h.m4
index 2027ab3c..e96be22f 100644
--- a/gl/m4/stdlib_h.m4
+++ b/gl/m4/stdlib_h.m4
@@ -1,10 +1,10 @@
-# stdlib_h.m4 serial 42
-dnl Copyright (C) 2007-2013 Free Software Foundation, Inc.
+# stdlib_h.m4 serial 66
+dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-AC_DEFUN([gl_STDLIB_H],
+AC_DEFUN_ONCE([gl_STDLIB_H],
 [
   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
   gl_NEXT_HEADERS([stdlib.h])
@@ -14,104 +14,187 @@ AC_DEFUN([gl_STDLIB_H],
   dnl guaranteed by C89.
   gl_WARN_ON_USE_PREPARE([[#include <stdlib.h>
 #if HAVE_SYS_LOADAVG_H
+/* OpenIndiana has a bug: <sys/time.h> must be included before
+   <sys/loadavg.h>.  */
+# include <sys/time.h>
 # include <sys/loadavg.h>
 #endif
 #if HAVE_RANDOM_H
 # include <random.h>
 #endif
-    ]], [_Exit atoll canonicalize_file_name getloadavg getsubopt grantpt
-    initstate initstate_r mkdtemp mkostemp mkostemps mkstemp mkstemps
-    posix_openpt ptsname ptsname_r random random_r realpath rpmatch
-    secure_getenv setenv setstate setstate_r srandom srandom_r
-    strtod strtoll strtoull unlockpt unsetenv])
+    ]], [_Exit aligned_alloc atoll canonicalize_file_name free
+    getloadavg getsubopt grantpt
+    initstate initstate_r mbtowc mkdtemp mkostemp mkostemps mkstemp mkstemps
+    posix_memalign posix_openpt ptsname ptsname_r qsort_r
+    random random_r reallocarray realpath rpmatch secure_getenv setenv
+    setstate setstate_r srandom srandom_r
+    strtod strtol strtold strtoll strtoul strtoull unlockpt unsetenv])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_CHECK_DECLS_ONCE([ecvt])
+  if test $ac_cv_have_decl_ecvt = no; then
+    HAVE_DECL_ECVT=0
+  fi
+  AC_CHECK_DECLS_ONCE([fcvt])
+  if test $ac_cv_have_decl_fcvt = no; then
+    HAVE_DECL_FCVT=0
+  fi
+  AC_CHECK_DECLS_ONCE([gcvt])
+  if test $ac_cv_have_decl_gcvt = no; then
+    HAVE_DECL_GCVT=0
+  fi
 ])
 
+# gl_STDLIB_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_STDLIB_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_STDLIB_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_STDLIB_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_STDLIB_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB__EXIT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ALIGNED_ALLOC])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ATOLL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CALLOC_GNU])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CALLOC_POSIX])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CANONICALIZE_FILE_NAME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FREE_POSIX])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETLOADAVG])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETSUBOPT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GRANTPT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MALLOC_GNU])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MALLOC_POSIX])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBTOWC])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MKDTEMP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MKOSTEMP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MKOSTEMPS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MKSTEMP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MKSTEMPS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_POSIX_MEMALIGN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_POSIX_OPENPT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PTSNAME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PTSNAME_R])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PUTENV])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_QSORT_R])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RANDOM])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RANDOM_R])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_REALLOCARRAY])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_REALLOC_GNU])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_REALLOC_POSIX])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_REALPATH])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RPMATCH])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SECURE_GETENV])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SETENV])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRTOD])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRTOL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRTOLD])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRTOLL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRTOUL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRTOULL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SYSTEM_POSIX])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_UNLOCKPT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_UNSETENV])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCTOMB])
+    dnl Support Microsoft deprecated alias function names by default.
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_ECVT], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_FCVT], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_GCVT], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_MKTEMP], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_PUTENV], [1])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_STDLIB_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_STDLIB_H_DEFAULTS],
 [
-  GNULIB__EXIT=0;         AC_SUBST([GNULIB__EXIT])
-  GNULIB_ATOLL=0;         AC_SUBST([GNULIB_ATOLL])
-  GNULIB_CALLOC_POSIX=0;  AC_SUBST([GNULIB_CALLOC_POSIX])
-  GNULIB_CANONICALIZE_FILE_NAME=0;  AC_SUBST([GNULIB_CANONICALIZE_FILE_NAME])
-  GNULIB_GETLOADAVG=0;    AC_SUBST([GNULIB_GETLOADAVG])
-  GNULIB_GETSUBOPT=0;     AC_SUBST([GNULIB_GETSUBOPT])
-  GNULIB_GRANTPT=0;       AC_SUBST([GNULIB_GRANTPT])
-  GNULIB_MALLOC_POSIX=0;  AC_SUBST([GNULIB_MALLOC_POSIX])
-  GNULIB_MBTOWC=0;        AC_SUBST([GNULIB_MBTOWC])
-  GNULIB_MKDTEMP=0;       AC_SUBST([GNULIB_MKDTEMP])
-  GNULIB_MKOSTEMP=0;      AC_SUBST([GNULIB_MKOSTEMP])
-  GNULIB_MKOSTEMPS=0;     AC_SUBST([GNULIB_MKOSTEMPS])
-  GNULIB_MKSTEMP=0;       AC_SUBST([GNULIB_MKSTEMP])
-  GNULIB_MKSTEMPS=0;      AC_SUBST([GNULIB_MKSTEMPS])
-  GNULIB_POSIX_OPENPT=0;  AC_SUBST([GNULIB_POSIX_OPENPT])
-  GNULIB_PTSNAME=0;       AC_SUBST([GNULIB_PTSNAME])
-  GNULIB_PTSNAME_R=0;     AC_SUBST([GNULIB_PTSNAME_R])
-  GNULIB_PUTENV=0;        AC_SUBST([GNULIB_PUTENV])
-  GNULIB_RANDOM=0;        AC_SUBST([GNULIB_RANDOM])
-  GNULIB_RANDOM_R=0;      AC_SUBST([GNULIB_RANDOM_R])
-  GNULIB_REALLOC_POSIX=0; AC_SUBST([GNULIB_REALLOC_POSIX])
-  GNULIB_REALPATH=0;      AC_SUBST([GNULIB_REALPATH])
-  GNULIB_RPMATCH=0;       AC_SUBST([GNULIB_RPMATCH])
-  GNULIB_SECURE_GETENV=0; AC_SUBST([GNULIB_SECURE_GETENV])
-  GNULIB_SETENV=0;        AC_SUBST([GNULIB_SETENV])
-  GNULIB_STRTOD=0;        AC_SUBST([GNULIB_STRTOD])
-  GNULIB_STRTOLL=0;       AC_SUBST([GNULIB_STRTOLL])
-  GNULIB_STRTOULL=0;      AC_SUBST([GNULIB_STRTOULL])
-  GNULIB_SYSTEM_POSIX=0;  AC_SUBST([GNULIB_SYSTEM_POSIX])
-  GNULIB_UNLOCKPT=0;      AC_SUBST([GNULIB_UNLOCKPT])
-  GNULIB_UNSETENV=0;      AC_SUBST([GNULIB_UNSETENV])
-  GNULIB_WCTOMB=0;        AC_SUBST([GNULIB_WCTOMB])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE__EXIT=1;              AC_SUBST([HAVE__EXIT])
+  HAVE_ALIGNED_ALLOC=1;      AC_SUBST([HAVE_ALIGNED_ALLOC])
   HAVE_ATOLL=1;              AC_SUBST([HAVE_ATOLL])
   HAVE_CANONICALIZE_FILE_NAME=1;  AC_SUBST([HAVE_CANONICALIZE_FILE_NAME])
+  HAVE_DECL_ECVT=1;          AC_SUBST([HAVE_DECL_ECVT])
+  HAVE_DECL_FCVT=1;          AC_SUBST([HAVE_DECL_FCVT])
+  HAVE_DECL_GCVT=1;          AC_SUBST([HAVE_DECL_GCVT])
   HAVE_DECL_GETLOADAVG=1;    AC_SUBST([HAVE_DECL_GETLOADAVG])
   HAVE_GETSUBOPT=1;          AC_SUBST([HAVE_GETSUBOPT])
   HAVE_GRANTPT=1;            AC_SUBST([HAVE_GRANTPT])
+  HAVE_INITSTATE=1;          AC_SUBST([HAVE_INITSTATE])
+  HAVE_DECL_INITSTATE=1;     AC_SUBST([HAVE_DECL_INITSTATE])
+  HAVE_MBTOWC=1;             AC_SUBST([HAVE_MBTOWC])
   HAVE_MKDTEMP=1;            AC_SUBST([HAVE_MKDTEMP])
   HAVE_MKOSTEMP=1;           AC_SUBST([HAVE_MKOSTEMP])
   HAVE_MKOSTEMPS=1;          AC_SUBST([HAVE_MKOSTEMPS])
   HAVE_MKSTEMP=1;            AC_SUBST([HAVE_MKSTEMP])
   HAVE_MKSTEMPS=1;           AC_SUBST([HAVE_MKSTEMPS])
+  HAVE_POSIX_MEMALIGN=1;     AC_SUBST([HAVE_POSIX_MEMALIGN])
   HAVE_POSIX_OPENPT=1;       AC_SUBST([HAVE_POSIX_OPENPT])
   HAVE_PTSNAME=1;            AC_SUBST([HAVE_PTSNAME])
   HAVE_PTSNAME_R=1;          AC_SUBST([HAVE_PTSNAME_R])
+  HAVE_QSORT_R=1;            AC_SUBST([HAVE_QSORT_R])
   HAVE_RANDOM=1;             AC_SUBST([HAVE_RANDOM])
   HAVE_RANDOM_H=1;           AC_SUBST([HAVE_RANDOM_H])
   HAVE_RANDOM_R=1;           AC_SUBST([HAVE_RANDOM_R])
+  HAVE_REALLOCARRAY=1;       AC_SUBST([HAVE_REALLOCARRAY])
   HAVE_REALPATH=1;           AC_SUBST([HAVE_REALPATH])
   HAVE_RPMATCH=1;            AC_SUBST([HAVE_RPMATCH])
   HAVE_SECURE_GETENV=1;      AC_SUBST([HAVE_SECURE_GETENV])
   HAVE_SETENV=1;             AC_SUBST([HAVE_SETENV])
   HAVE_DECL_SETENV=1;        AC_SUBST([HAVE_DECL_SETENV])
+  HAVE_SETSTATE=1;           AC_SUBST([HAVE_SETSTATE])
+  HAVE_DECL_SETSTATE=1;      AC_SUBST([HAVE_DECL_SETSTATE])
   HAVE_STRTOD=1;             AC_SUBST([HAVE_STRTOD])
+  HAVE_STRTOL=1;             AC_SUBST([HAVE_STRTOL])
+  HAVE_STRTOLD=1;            AC_SUBST([HAVE_STRTOLD])
   HAVE_STRTOLL=1;            AC_SUBST([HAVE_STRTOLL])
+  HAVE_STRTOUL=1;            AC_SUBST([HAVE_STRTOUL])
   HAVE_STRTOULL=1;           AC_SUBST([HAVE_STRTOULL])
   HAVE_STRUCT_RANDOM_DATA=1; AC_SUBST([HAVE_STRUCT_RANDOM_DATA])
   HAVE_SYS_LOADAVG_H=0;      AC_SUBST([HAVE_SYS_LOADAVG_H])
   HAVE_UNLOCKPT=1;           AC_SUBST([HAVE_UNLOCKPT])
   HAVE_DECL_UNSETENV=1;      AC_SUBST([HAVE_DECL_UNSETENV])
-  REPLACE_CALLOC=0;          AC_SUBST([REPLACE_CALLOC])
+  REPLACE_ALIGNED_ALLOC=0;   AC_SUBST([REPLACE_ALIGNED_ALLOC])
+  REPLACE_CALLOC_FOR_CALLOC_GNU=0;    AC_SUBST([REPLACE_CALLOC_FOR_CALLOC_GNU])
+  REPLACE_CALLOC_FOR_CALLOC_POSIX=0;  AC_SUBST([REPLACE_CALLOC_FOR_CALLOC_POSIX])
   REPLACE_CANONICALIZE_FILE_NAME=0;  AC_SUBST([REPLACE_CANONICALIZE_FILE_NAME])
-  REPLACE_MALLOC=0;          AC_SUBST([REPLACE_MALLOC])
+  REPLACE_FREE=0;            AC_SUBST([REPLACE_FREE])
+  REPLACE_INITSTATE=0;       AC_SUBST([REPLACE_INITSTATE])
+  REPLACE_MALLOC_FOR_MALLOC_GNU=0;    AC_SUBST([REPLACE_MALLOC_FOR_MALLOC_GNU])
+  REPLACE_MALLOC_FOR_MALLOC_POSIX=0;  AC_SUBST([REPLACE_MALLOC_FOR_MALLOC_POSIX])
   REPLACE_MBTOWC=0;          AC_SUBST([REPLACE_MBTOWC])
   REPLACE_MKSTEMP=0;         AC_SUBST([REPLACE_MKSTEMP])
+  REPLACE_POSIX_MEMALIGN=0;  AC_SUBST([REPLACE_POSIX_MEMALIGN])
   REPLACE_PTSNAME=0;         AC_SUBST([REPLACE_PTSNAME])
   REPLACE_PTSNAME_R=0;       AC_SUBST([REPLACE_PTSNAME_R])
   REPLACE_PUTENV=0;          AC_SUBST([REPLACE_PUTENV])
+  REPLACE_QSORT_R=0;         AC_SUBST([REPLACE_QSORT_R])
+  REPLACE_RANDOM=0;          AC_SUBST([REPLACE_RANDOM])
   REPLACE_RANDOM_R=0;        AC_SUBST([REPLACE_RANDOM_R])
-  REPLACE_REALLOC=0;         AC_SUBST([REPLACE_REALLOC])
+  REPLACE_REALLOC_FOR_REALLOC_GNU=0;    AC_SUBST([REPLACE_REALLOC_FOR_REALLOC_GNU])
+  REPLACE_REALLOC_FOR_REALLOC_POSIX=0;  AC_SUBST([REPLACE_REALLOC_FOR_REALLOC_POSIX])
+  REPLACE_REALLOCARRAY=0;    AC_SUBST([REPLACE_REALLOCARRAY])
   REPLACE_REALPATH=0;        AC_SUBST([REPLACE_REALPATH])
   REPLACE_SETENV=0;          AC_SUBST([REPLACE_SETENV])
+  REPLACE_SETSTATE=0;        AC_SUBST([REPLACE_SETSTATE])
   REPLACE_STRTOD=0;          AC_SUBST([REPLACE_STRTOD])
+  REPLACE_STRTOL=0;          AC_SUBST([REPLACE_STRTOL])
+  REPLACE_STRTOLD=0;         AC_SUBST([REPLACE_STRTOLD])
+  REPLACE_STRTOLL=0;         AC_SUBST([REPLACE_STRTOLL])
+  REPLACE_STRTOUL=0;         AC_SUBST([REPLACE_STRTOUL])
+  REPLACE_STRTOULL=0;        AC_SUBST([REPLACE_STRTOULL])
   REPLACE_UNSETENV=0;        AC_SUBST([REPLACE_UNSETENV])
   REPLACE_WCTOMB=0;          AC_SUBST([REPLACE_WCTOMB])
 ])
diff --git a/gl/m4/strcase.m4 b/gl/m4/strcase.m4
index 22bf57c9..3cf740d2 100644
--- a/gl/m4/strcase.m4
+++ b/gl/m4/strcase.m4
@@ -1,5 +1,5 @@
-# strcase.m4 serial 11
-dnl Copyright (C) 2002, 2005-2013 Free Software Foundation, Inc.
+# strcase.m4 serial 12
+dnl Copyright (C) 2002, 2005-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -12,7 +12,7 @@ AC_DEFUN([gl_STRCASE],
 
 AC_DEFUN([gl_FUNC_STRCASECMP],
 [
-  AC_REQUIRE([gl_HEADER_STRINGS_H_DEFAULTS])
+  AC_REQUIRE([gl_STRINGS_H_DEFAULTS])
   AC_CHECK_FUNCS([strcasecmp])
   if test $ac_cv_func_strcasecmp = no; then
     HAVE_STRCASECMP=0
@@ -21,7 +21,7 @@ AC_DEFUN([gl_FUNC_STRCASECMP],
 
 AC_DEFUN([gl_FUNC_STRNCASECMP],
 [
-  AC_REQUIRE([gl_HEADER_STRINGS_H_DEFAULTS])
+  AC_REQUIRE([gl_STRINGS_H_DEFAULTS])
   AC_CHECK_FUNCS([strncasecmp])
   if test $ac_cv_func_strncasecmp = yes; then
     HAVE_STRNCASECMP=1
diff --git a/gl/m4/strcasestr.m4 b/gl/m4/strcasestr.m4
index 8681a6a4..971e0b23 100644
--- a/gl/m4/strcasestr.m4
+++ b/gl/m4/strcasestr.m4
@@ -1,5 +1,5 @@
-# strcasestr.m4 serial 21
-dnl Copyright (C) 2005, 2007-2013 Free Software Foundation, Inc.
+# strcasestr.m4 serial 28
+dnl Copyright (C) 2005, 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -7,7 +7,7 @@ dnl with or without modifications, as long as this notice is preserved.
 dnl Check that strcasestr is present and works.
 AC_DEFUN([gl_FUNC_STRCASESTR_SIMPLE],
 [
-  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_REQUIRE([gl_STRING_H_DEFAULTS])
 
   dnl Persuade glibc <string.h> to declare strcasestr().
   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
@@ -17,28 +17,38 @@ AC_DEFUN([gl_FUNC_STRCASESTR_SIMPLE],
   if test $ac_cv_func_strcasestr = no; then
     HAVE_STRCASESTR=0
   else
-    if test "$gl_cv_func_memchr_works" != yes; then
+    if test $REPLACE_MEMCHR = 1; then
       REPLACE_STRCASESTR=1
     else
-      dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092.
+      dnl Detect https://sourceware.org/bugzilla/show_bug.cgi?id=12092
+      dnl and https://sourceware.org/bugzilla/show_bug.cgi?id=23637.
       AC_CACHE_CHECK([whether strcasestr works],
         [gl_cv_func_strcasestr_works_always],
-        [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
-#include <string.h> /* for strcasestr */
+        [AC_RUN_IFELSE(
+           [AC_LANG_PROGRAM([[
+#include <string.h> /* for __GNU_LIBRARY__, strcasestr */
+#ifdef __GNU_LIBRARY__
+ #include <features.h>
+ #if __GLIBC__ == 2 && __GLIBC_MINOR__ == 28
+  Unlucky user
+ #endif
+#endif
 #define P "_EF_BF_BD"
 #define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
 #define NEEDLE P P P P P
-]], [[return !!strcasestr (HAYSTACK, NEEDLE);
-      ]])],
-          [gl_cv_func_strcasestr_works_always=yes],
-          [gl_cv_func_strcasestr_works_always=no],
-          [dnl glibc 2.12 and cygwin 1.7.7 have a known bug.  uClibc is not
-           dnl affected, since it uses different source code for strcasestr
-           dnl than glibc.
-           dnl Assume that it works on all other platforms, even if it is not
-           dnl linear.
-           AC_EGREP_CPP([Lucky user],
-             [
+]],
+              [[return !!strcasestr (HAYSTACK, NEEDLE);
+              ]])],
+           [gl_cv_func_strcasestr_works_always=yes],
+           [gl_cv_func_strcasestr_works_always=no],
+           [dnl glibc 2.12 and cygwin 1.7.7 have a known bug.  uClibc is not
+            dnl affected, since it uses different source code for strcasestr
+            dnl than glibc.
+            dnl Assume that it works on all other platforms, even if it is not
+            dnl linear.
+            AC_EGREP_CPP([Lucky user],
+              [
+#include <string.h> /* for __GNU_LIBRARY__ */
 #ifdef __GNU_LIBRARY__
  #include <features.h>
  #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
@@ -53,10 +63,10 @@ AC_DEFUN([gl_FUNC_STRCASESTR_SIMPLE],
 #else
   Lucky user
 #endif
-             ],
-             [gl_cv_func_strcasestr_works_always="guessing yes"],
-             [gl_cv_func_strcasestr_works_always="guessing no"])
-          ])
+              ],
+              [gl_cv_func_strcasestr_works_always="guessing yes"],
+              [gl_cv_func_strcasestr_works_always="$gl_cross_guess_normal"])
+           ])
         ])
       case "$gl_cv_func_strcasestr_works_always" in
         *yes) ;;
@@ -80,7 +90,7 @@ AC_DEFUN([gl_FUNC_STRCASESTR],
 #include <string.h> /* for strcasestr */
 #include <stdlib.h> /* for malloc */
 #include <unistd.h> /* for alarm */
-static void quit (int sig) { exit (sig + 128); }
+static void quit (int sig) { _exit (sig + 128); }
 ]], [[
     int result = 0;
     size_t m = 1000000;
@@ -102,6 +112,9 @@ static void quit (int sig) { exit (sig + 128); }
         if (!strcasestr (haystack, needle))
           result |= 1;
       }
+    /* Free allocated memory, in case some sanitizer is watching.  */
+    free (haystack);
+    free (needle);
     return result;
     ]])],
         [gl_cv_func_strcasestr_linear=yes], [gl_cv_func_strcasestr_linear=no],
@@ -124,7 +137,7 @@ static void quit (int sig) { exit (sig + 128); }
 #endif
            ],
            [gl_cv_func_strcasestr_linear="guessing yes"],
-           [gl_cv_func_strcasestr_linear="guessing no"])
+           [gl_cv_func_strcasestr_linear="$gl_cross_guess_normal"])
         ])
       ])
     case "$gl_cv_func_strcasestr_linear" in
diff --git a/gl/m4/strerror.m4 b/gl/m4/strerror.m4
index 3989844b..8879eb08 100644
--- a/gl/m4/strerror.m4
+++ b/gl/m4/strerror.m4
@@ -1,19 +1,19 @@
-# strerror.m4 serial 17
-dnl Copyright (C) 2002, 2007-2013 Free Software Foundation, Inc.
+# strerror.m4 serial 23
+dnl Copyright (C) 2002, 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_STRERROR],
 [
-  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_REQUIRE([gl_STRING_H_DEFAULTS])
   AC_REQUIRE([gl_HEADER_ERRNO_H])
   AC_REQUIRE([gl_FUNC_STRERROR_0])
   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
   m4_ifdef([gl_FUNC_STRERROR_R_WORKS], [
     AC_REQUIRE([gl_FUNC_STRERROR_R_WORKS])
   ])
-  if test "$ERRNO_H:$REPLACE_STRERROR_0" = :0; then
+  if test "$GL_GENERATE_ERRNO_H:$REPLACE_STRERROR_0" = false:0; then
     AC_CACHE_CHECK([for working strerror function],
      [gl_cv_func_working_strerror],
      [AC_RUN_IFELSE(
@@ -24,10 +24,12 @@ AC_DEFUN([gl_FUNC_STRERROR],
         [gl_cv_func_working_strerror=yes],
         [gl_cv_func_working_strerror=no],
         [case "$host_os" in
-                   # Guess yes on glibc systems.
-           *-gnu*) gl_cv_func_working_strerror="guessing yes" ;;
-                   # If we don't know, assume the worst.
-           *)      gl_cv_func_working_strerror="guessing no" ;;
+                          # Guess yes on glibc systems.
+           *-gnu* | gnu*) gl_cv_func_working_strerror="guessing yes" ;;
+                          # Guess yes on musl systems.
+           *-musl*)       gl_cv_func_working_strerror="guessing yes" ;;
+                          # If we don't know, obey --enable-cross-guesses.
+           *)             gl_cv_func_working_strerror="$gl_cross_guess_normal" ;;
          esac
         ])
     ])
@@ -78,10 +80,14 @@ AC_DEFUN([gl_FUNC_STRERROR_0],
       [gl_cv_func_strerror_0_works=yes],
       [gl_cv_func_strerror_0_works=no],
       [case "$host_os" in
-                 # Guess yes on glibc systems.
-         *-gnu*) gl_cv_func_strerror_0_works="guessing yes" ;;
-                 # If we don't know, assume the worst.
-         *)      gl_cv_func_strerror_0_works="guessing no" ;;
+                        # Guess yes on glibc systems.
+         *-gnu* | gnu*) gl_cv_func_strerror_0_works="guessing yes" ;;
+                        # Guess yes on musl systems.
+         *-musl*)       gl_cv_func_strerror_0_works="guessing yes" ;;
+                        # Guess yes on native Windows.
+         mingw*)        gl_cv_func_strerror_0_works="guessing yes" ;;
+                        # If we don't know, obey --enable-cross-guesses.
+         *)             gl_cv_func_strerror_0_works="$gl_cross_guess_normal" ;;
        esac
       ])
   ])
diff --git a/gl/m4/string_h.m4 b/gl/m4/string_h.m4
index cc5fbbb3..5da3cc25 100644
--- a/gl/m4/string_h.m4
+++ b/gl/m4/string_h.m4
@@ -1,25 +1,19 @@
 # Configure a GNU-like replacement for <string.h>.
 
-# Copyright (C) 2007-2013 Free Software Foundation, Inc.
+# Copyright (C) 2007-2023 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
-# serial 21
+# serial 35
 
 # Written by Paul Eggert.
 
-AC_DEFUN([gl_HEADER_STRING_H],
+AC_DEFUN_ONCE([gl_STRING_H],
 [
-  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
-  dnl once only, before all statements that occur in other macros.
-  AC_REQUIRE([gl_HEADER_STRING_H_BODY])
-])
-
-AC_DEFUN([gl_HEADER_STRING_H_BODY],
-[
-  AC_REQUIRE([AC_C_RESTRICT])
-  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only, before all statements
+  dnl that occur in other macros.
+  AC_REQUIRE([gl_STRING_H_DEFAULTS])
   gl_NEXT_HEADERS([string.h])
 
   dnl Check for declarations of anything we want to poison if the
@@ -27,66 +21,95 @@ AC_DEFUN([gl_HEADER_STRING_H_BODY],
   dnl guaranteed by C89.
   gl_WARN_ON_USE_PREPARE([[#include <string.h>
     ]],
-    [ffsl ffsll memmem mempcpy memrchr rawmemchr stpcpy stpncpy strchrnul
+    [explicit_bzero ffsl ffsll memmem mempcpy memrchr memset_explicit
+     rawmemchr stpcpy stpncpy strchrnul
      strdup strncat strndup strnlen strpbrk strsep strcasestr strtok_r
-     strerror_r strsignal strverscmp])
+     strerror_r strerrorname_np sigabbrev_np sigdescr_np strsignal strverscmp])
+
+  AC_REQUIRE([AC_C_RESTRICT])
 ])
 
+# gl_STRING_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_STRING_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_STRING_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
-AC_DEFUN([gl_HEADER_STRING_H_DEFAULTS],
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_STRING_H_REQUIRE_DEFAULTS],
 [
-  GNULIB_FFSL=0;        AC_SUBST([GNULIB_FFSL])
-  GNULIB_FFSLL=0;       AC_SUBST([GNULIB_FFSLL])
-  GNULIB_MEMCHR=0;      AC_SUBST([GNULIB_MEMCHR])
-  GNULIB_MEMMEM=0;      AC_SUBST([GNULIB_MEMMEM])
-  GNULIB_MEMPCPY=0;     AC_SUBST([GNULIB_MEMPCPY])
-  GNULIB_MEMRCHR=0;     AC_SUBST([GNULIB_MEMRCHR])
-  GNULIB_RAWMEMCHR=0;   AC_SUBST([GNULIB_RAWMEMCHR])
-  GNULIB_STPCPY=0;      AC_SUBST([GNULIB_STPCPY])
-  GNULIB_STPNCPY=0;     AC_SUBST([GNULIB_STPNCPY])
-  GNULIB_STRCHRNUL=0;   AC_SUBST([GNULIB_STRCHRNUL])
-  GNULIB_STRDUP=0;      AC_SUBST([GNULIB_STRDUP])
-  GNULIB_STRNCAT=0;     AC_SUBST([GNULIB_STRNCAT])
-  GNULIB_STRNDUP=0;     AC_SUBST([GNULIB_STRNDUP])
-  GNULIB_STRNLEN=0;     AC_SUBST([GNULIB_STRNLEN])
-  GNULIB_STRPBRK=0;     AC_SUBST([GNULIB_STRPBRK])
-  GNULIB_STRSEP=0;      AC_SUBST([GNULIB_STRSEP])
-  GNULIB_STRSTR=0;      AC_SUBST([GNULIB_STRSTR])
-  GNULIB_STRCASESTR=0;  AC_SUBST([GNULIB_STRCASESTR])
-  GNULIB_STRTOK_R=0;    AC_SUBST([GNULIB_STRTOK_R])
-  GNULIB_MBSLEN=0;      AC_SUBST([GNULIB_MBSLEN])
-  GNULIB_MBSNLEN=0;     AC_SUBST([GNULIB_MBSNLEN])
-  GNULIB_MBSCHR=0;      AC_SUBST([GNULIB_MBSCHR])
-  GNULIB_MBSRCHR=0;     AC_SUBST([GNULIB_MBSRCHR])
-  GNULIB_MBSSTR=0;      AC_SUBST([GNULIB_MBSSTR])
-  GNULIB_MBSCASECMP=0;  AC_SUBST([GNULIB_MBSCASECMP])
-  GNULIB_MBSNCASECMP=0; AC_SUBST([GNULIB_MBSNCASECMP])
-  GNULIB_MBSPCASECMP=0; AC_SUBST([GNULIB_MBSPCASECMP])
-  GNULIB_MBSCASESTR=0;  AC_SUBST([GNULIB_MBSCASESTR])
-  GNULIB_MBSCSPN=0;     AC_SUBST([GNULIB_MBSCSPN])
-  GNULIB_MBSPBRK=0;     AC_SUBST([GNULIB_MBSPBRK])
-  GNULIB_MBSSPN=0;      AC_SUBST([GNULIB_MBSSPN])
-  GNULIB_MBSSEP=0;      AC_SUBST([GNULIB_MBSSEP])
-  GNULIB_MBSTOK_R=0;    AC_SUBST([GNULIB_MBSTOK_R])
-  GNULIB_STRERROR=0;    AC_SUBST([GNULIB_STRERROR])
-  GNULIB_STRERROR_R=0;  AC_SUBST([GNULIB_STRERROR_R])
-  GNULIB_STRSIGNAL=0;   AC_SUBST([GNULIB_STRSIGNAL])
-  GNULIB_STRVERSCMP=0;  AC_SUBST([GNULIB_STRVERSCMP])
-  HAVE_MBSLEN=0;        AC_SUBST([HAVE_MBSLEN])
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_STRING_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXPLICIT_BZERO])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FFSL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FFSLL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MEMCHR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MEMMEM])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MEMPCPY])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MEMRCHR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MEMSET_EXPLICIT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RAWMEMCHR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STPCPY])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STPNCPY])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRCHRNUL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRDUP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRNCAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRNDUP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRNLEN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRPBRK])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRSEP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRSTR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRCASESTR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRTOK_R])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSLEN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSNLEN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSCHR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSRCHR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSSTR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSCASECMP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSNCASECMP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSPCASECMP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSCASESTR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSCSPN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSPBRK])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSSPN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSSEP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSTOK_R])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRERROR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRERROR_R])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRERRORNAME_NP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SIGABBREV_NP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SIGDESCR_NP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRSIGNAL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRVERSCMP])
+    dnl Support Microsoft deprecated alias function names by default.
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_MEMCCPY], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_STRDUP], [1])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_STRING_H_MODULE_INDICATOR_DEFAULTS])
+  dnl Make sure the shell variable for GNULIB_FREE_POSIX is initialized.
+  gl_STDLIB_H_REQUIRE_DEFAULTS
+  AC_REQUIRE([gl_STRING_H_DEFAULTS])
+])
+
+AC_DEFUN([gl_STRING_H_DEFAULTS],
+[
+  HAVE_MBSLEN=0;             AC_SUBST([HAVE_MBSLEN])
   dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_EXPLICIT_BZERO=1;        AC_SUBST([HAVE_EXPLICIT_BZERO])
   HAVE_FFSL=1;                  AC_SUBST([HAVE_FFSL])
   HAVE_FFSLL=1;                 AC_SUBST([HAVE_FFSLL])
-  HAVE_MEMCHR=1;                AC_SUBST([HAVE_MEMCHR])
   HAVE_DECL_MEMMEM=1;           AC_SUBST([HAVE_DECL_MEMMEM])
   HAVE_MEMPCPY=1;               AC_SUBST([HAVE_MEMPCPY])
+  HAVE_MEMSET_EXPLICIT=1;       AC_SUBST([HAVE_MEMSET_EXPLICIT])
   HAVE_DECL_MEMRCHR=1;          AC_SUBST([HAVE_DECL_MEMRCHR])
   HAVE_RAWMEMCHR=1;             AC_SUBST([HAVE_RAWMEMCHR])
   HAVE_STPCPY=1;                AC_SUBST([HAVE_STPCPY])
@@ -100,21 +123,26 @@ AC_DEFUN([gl_HEADER_STRING_H_DEFAULTS],
   HAVE_STRCASESTR=1;            AC_SUBST([HAVE_STRCASESTR])
   HAVE_DECL_STRTOK_R=1;         AC_SUBST([HAVE_DECL_STRTOK_R])
   HAVE_DECL_STRERROR_R=1;       AC_SUBST([HAVE_DECL_STRERROR_R])
+  HAVE_STRERRORNAME_NP=1;       AC_SUBST([HAVE_STRERRORNAME_NP])
+  HAVE_SIGABBREV_NP=1;          AC_SUBST([HAVE_SIGABBREV_NP])
+  HAVE_SIGDESCR_NP=1;           AC_SUBST([HAVE_SIGDESCR_NP])
   HAVE_DECL_STRSIGNAL=1;        AC_SUBST([HAVE_DECL_STRSIGNAL])
   HAVE_STRVERSCMP=1;            AC_SUBST([HAVE_STRVERSCMP])
+  REPLACE_FFSLL=0;              AC_SUBST([REPLACE_FFSLL])
   REPLACE_MEMCHR=0;             AC_SUBST([REPLACE_MEMCHR])
   REPLACE_MEMMEM=0;             AC_SUBST([REPLACE_MEMMEM])
   REPLACE_STPNCPY=0;            AC_SUBST([REPLACE_STPNCPY])
+  REPLACE_STRCHRNUL=0;          AC_SUBST([REPLACE_STRCHRNUL])
   REPLACE_STRDUP=0;             AC_SUBST([REPLACE_STRDUP])
+  REPLACE_STRNCAT=0;            AC_SUBST([REPLACE_STRNCAT])
+  REPLACE_STRNDUP=0;            AC_SUBST([REPLACE_STRNDUP])
+  REPLACE_STRNLEN=0;            AC_SUBST([REPLACE_STRNLEN])
   REPLACE_STRSTR=0;             AC_SUBST([REPLACE_STRSTR])
   REPLACE_STRCASESTR=0;         AC_SUBST([REPLACE_STRCASESTR])
-  REPLACE_STRCHRNUL=0;          AC_SUBST([REPLACE_STRCHRNUL])
+  REPLACE_STRTOK_R=0;           AC_SUBST([REPLACE_STRTOK_R])
   REPLACE_STRERROR=0;           AC_SUBST([REPLACE_STRERROR])
   REPLACE_STRERROR_R=0;         AC_SUBST([REPLACE_STRERROR_R])
-  REPLACE_STRNCAT=0;            AC_SUBST([REPLACE_STRNCAT])
-  REPLACE_STRNDUP=0;            AC_SUBST([REPLACE_STRNDUP])
-  REPLACE_STRNLEN=0;            AC_SUBST([REPLACE_STRNLEN])
+  REPLACE_STRERRORNAME_NP=0;    AC_SUBST([REPLACE_STRERRORNAME_NP])
   REPLACE_STRSIGNAL=0;          AC_SUBST([REPLACE_STRSIGNAL])
-  REPLACE_STRTOK_R=0;           AC_SUBST([REPLACE_STRTOK_R])
   UNDEFINE_STRTOK_R=0;          AC_SUBST([UNDEFINE_STRTOK_R])
 ])
diff --git a/gl/m4/strings_h.m4 b/gl/m4/strings_h.m4
index 76ef2424..4c41221b 100644
--- a/gl/m4/strings_h.m4
+++ b/gl/m4/strings_h.m4
@@ -1,21 +1,16 @@
 # Configure a replacement for <strings.h>.
-# serial 6
+# serial 9
 
-# Copyright (C) 2007, 2009-2013 Free Software Foundation, Inc.
+# Copyright (C) 2007, 2009-2023 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
-AC_DEFUN([gl_HEADER_STRINGS_H],
+AC_DEFUN_ONCE([gl_STRINGS_H],
 [
-  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
-  dnl once only, before all statements that occur in other macros.
-  AC_REQUIRE([gl_HEADER_STRINGS_H_BODY])
-])
-
-AC_DEFUN([gl_HEADER_STRINGS_H_BODY],
-[
-  AC_REQUIRE([gl_HEADER_STRINGS_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only, before all statements
+  dnl that occur in other macros.
+  AC_REQUIRE([gl_STRINGS_H_DEFAULTS])
 
   gl_CHECK_NEXT_HEADERS([strings.h])
   if test $ac_cv_header_strings_h = yes; then
@@ -35,16 +30,31 @@ AC_DEFUN([gl_HEADER_STRINGS_H_BODY],
     ]], [ffs strcasecmp strncasecmp])
 ])
 
+# gl_STRINGS_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_STRINGS_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_HEADER_STRINGS_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_STRINGS_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
 ])
 
-AC_DEFUN([gl_HEADER_STRINGS_H_DEFAULTS],
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_STRINGS_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_STRINGS_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FFS])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_STRINGS_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_STRINGS_H_DEFAULTS])
+])
+
+AC_DEFUN([gl_STRINGS_H_DEFAULTS],
 [
-  GNULIB_FFS=0;            AC_SUBST([GNULIB_FFS])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_FFS=1;              AC_SUBST([HAVE_FFS])
   HAVE_STRCASECMP=1;       AC_SUBST([HAVE_STRCASECMP])
diff --git a/gl/m4/strndup.m4 b/gl/m4/strndup.m4
deleted file mode 100644
index a1f82743..00000000
--- a/gl/m4/strndup.m4
+++ /dev/null
@@ -1,55 +0,0 @@
-# strndup.m4 serial 21
-dnl Copyright (C) 2002-2003, 2005-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-AC_DEFUN([gl_FUNC_STRNDUP],
-[
-  dnl Persuade glibc <string.h> to declare strndup().
-  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
-
-  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
-  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
-  AC_CHECK_DECLS_ONCE([strndup])
-  AC_CHECK_FUNCS_ONCE([strndup])
-  if test $ac_cv_have_decl_strndup = no; then
-    HAVE_DECL_STRNDUP=0
-  fi
-
-  if test $ac_cv_func_strndup = yes; then
-    HAVE_STRNDUP=1
-    # AIX 4.3.3, AIX 5.1 have a function that fails to add the terminating '\0'.
-    AC_CACHE_CHECK([for working strndup], [gl_cv_func_strndup_works],
-      [AC_RUN_IFELSE([
-         AC_LANG_PROGRAM([[#include <string.h>
-                           #include <stdlib.h>]], [[
-#if !HAVE_DECL_STRNDUP
-  extern
-  #ifdef __cplusplus
-  "C"
-  #endif
-  char *strndup (const char *, size_t);
-#endif
-  char *s;
-  s = strndup ("some longer string", 15);
-  free (s);
-  s = strndup ("shorter string", 13);
-  return s[13] != '\0';]])],
-         [gl_cv_func_strndup_works=yes],
-         [gl_cv_func_strndup_works=no],
-         [
-changequote(,)dnl
-          case $host_os in
-            aix | aix[3-6]*) gl_cv_func_strndup_works="guessing no";;
-            *)               gl_cv_func_strndup_works="guessing yes";;
-          esac
-changequote([,])dnl
-         ])])
-    case $gl_cv_func_strndup_works in
-      *no) REPLACE_STRNDUP=1 ;;
-    esac
-  else
-    HAVE_STRNDUP=0
-  fi
-])
diff --git a/gl/m4/strnlen.m4 b/gl/m4/strnlen.m4
deleted file mode 100644
index eae82b77..00000000
--- a/gl/m4/strnlen.m4
+++ /dev/null
@@ -1,30 +0,0 @@
-# strnlen.m4 serial 13
-dnl Copyright (C) 2002-2003, 2005-2007, 2009-2013 Free Software Foundation,
-dnl Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-AC_DEFUN([gl_FUNC_STRNLEN],
-[
-  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
-
-  dnl Persuade glibc <string.h> to declare strnlen().
-  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
-
-  AC_CHECK_DECLS_ONCE([strnlen])
-  if test $ac_cv_have_decl_strnlen = no; then
-    HAVE_DECL_STRNLEN=0
-  else
-    m4_pushdef([AC_LIBOBJ], [:])
-    dnl Note: AC_FUNC_STRNLEN does AC_LIBOBJ([strnlen]).
-    AC_FUNC_STRNLEN
-    m4_popdef([AC_LIBOBJ])
-    if test $ac_cv_func_strnlen_working = no; then
-      REPLACE_STRNLEN=1
-    fi
-  fi
-])
-
-# Prerequisites of lib/strnlen.c.
-AC_DEFUN([gl_PREREQ_STRNLEN], [:])
diff --git a/gl/m4/strsep.m4 b/gl/m4/strsep.m4
index 825fdb81..e0da09a3 100644
--- a/gl/m4/strsep.m4
+++ b/gl/m4/strsep.m4
@@ -1,5 +1,5 @@
-# strsep.m4 serial 10
-dnl Copyright (C) 2002-2004, 2007, 2009-2013 Free Software Foundation, Inc.
+# strsep.m4 serial 11
+dnl Copyright (C) 2002-2004, 2007, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -12,7 +12,7 @@ AC_DEFUN([gl_FUNC_STRSEP],
   dnl The strsep() declaration in lib/string.in.h uses 'restrict'.
   AC_REQUIRE([AC_C_RESTRICT])
 
-  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_REQUIRE([gl_STRING_H_DEFAULTS])
   AC_CHECK_FUNCS([strsep])
   if test $ac_cv_func_strsep = no; then
     HAVE_STRSEP=0
diff --git a/gl/m4/strstr.m4 b/gl/m4/strstr.m4
index c486bdb0..7de203a7 100644
--- a/gl/m4/strstr.m4
+++ b/gl/m4/strstr.m4
@@ -1,5 +1,5 @@
-# strstr.m4 serial 16
-dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
+# strstr.m4 serial 24
+dnl Copyright (C) 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -7,30 +7,40 @@ dnl with or without modifications, as long as this notice is preserved.
 dnl Check that strstr works.
 AC_DEFUN([gl_FUNC_STRSTR_SIMPLE],
 [
-  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_REQUIRE([gl_STRING_H_DEFAULTS])
   AC_REQUIRE([gl_FUNC_MEMCHR])
-  if test "$gl_cv_func_memchr_works" != yes; then
+  if test $REPLACE_MEMCHR = 1; then
     REPLACE_STRSTR=1
   else
-    dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092.
+    dnl Detect https://sourceware.org/bugzilla/show_bug.cgi?id=12092
+    dnl and https://sourceware.org/bugzilla/show_bug.cgi?id=23637.
     AC_CACHE_CHECK([whether strstr works],
       [gl_cv_func_strstr_works_always],
-      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
-#include <string.h> /* for strstr */
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM([[
+#include <string.h> /* for __GNU_LIBRARY__, strstr */
+#ifdef __GNU_LIBRARY__
+ #include <features.h>
+ #if __GLIBC__ == 2 && __GLIBC_MINOR__ == 28
+  Unlucky user
+ #endif
+#endif
 #define P "_EF_BF_BD"
 #define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
 #define NEEDLE P P P P P
-]], [[return !!strstr (HAYSTACK, NEEDLE);
-    ]])],
-        [gl_cv_func_strstr_works_always=yes],
-        [gl_cv_func_strstr_works_always=no],
-        [dnl glibc 2.12 and cygwin 1.7.7 have a known bug.  uClibc is not
-         dnl affected, since it uses different source code for strstr than
-         dnl glibc.
-         dnl Assume that it works on all other platforms, even if it is not
-         dnl linear.
-         AC_EGREP_CPP([Lucky user],
-           [
+]],
+            [[return !!strstr (HAYSTACK, NEEDLE);
+            ]])],
+         [gl_cv_func_strstr_works_always=yes],
+         [gl_cv_func_strstr_works_always=no],
+         [dnl glibc 2.12 and cygwin 1.7.7 have a known bug.  uClibc is not
+          dnl affected, since it uses different source code for strstr than
+          dnl glibc.
+          dnl Assume that it works on all other platforms, even if it is not
+          dnl linear.
+          AC_EGREP_CPP([Lucky user],
+            [
+#include <string.h> /* for __GNU_LIBRARY__ */
 #ifdef __GNU_LIBRARY__
  #include <features.h>
  #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
@@ -45,10 +55,10 @@ AC_DEFUN([gl_FUNC_STRSTR_SIMPLE],
 #else
   Lucky user
 #endif
-           ],
-           [gl_cv_func_strstr_works_always="guessing yes"],
-           [gl_cv_func_strstr_works_always="guessing no"])
-        ])
+            ],
+            [gl_cv_func_strstr_works_always="guessing yes"],
+            [gl_cv_func_strstr_works_always="$gl_cross_guess_normal"])
+         ])
       ])
     case "$gl_cv_func_strstr_works_always" in
       *yes) ;;
@@ -67,11 +77,17 @@ AC_DEFUN([gl_FUNC_STRSTR],
     AC_CACHE_CHECK([whether strstr works in linear time],
       [gl_cv_func_strstr_linear],
       [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#ifdef __MVS__
+/* z/OS does not deliver signals while strstr() is running (thanks to
+   restrictions on its LE runtime), which prevents us from limiting the
+   running time of this test.  */
+# error "This test does not work properly on z/OS"
+#endif
 #include <signal.h> /* for signal */
 #include <string.h> /* for strstr */
 #include <stdlib.h> /* for malloc */
 #include <unistd.h> /* for alarm */
-static void quit (int sig) { exit (sig + 128); }
+static void quit (int sig) { _exit (sig + 128); }
 ]], [[
     int result = 0;
     size_t m = 1000000;
@@ -93,6 +109,9 @@ static void quit (int sig) { exit (sig + 128); }
         if (!strstr (haystack, needle))
           result |= 1;
       }
+    /* Free allocated memory, in case some sanitizer is watching.  */
+    free (haystack);
+    free (needle);
     return result;
     ]])],
         [gl_cv_func_strstr_linear=yes], [gl_cv_func_strstr_linear=no],
@@ -117,7 +136,7 @@ static void quit (int sig) { exit (sig + 128); }
 #endif
            ],
            [gl_cv_func_strstr_linear="guessing yes"],
-           [gl_cv_func_strstr_linear="guessing no"])
+           [gl_cv_func_strstr_linear="$gl_cross_guess_normal"])
         ])
       ])
     case "$gl_cv_func_strstr_linear" in
diff --git a/gl/m4/sys_socket_h.m4 b/gl/m4/sys_socket_h.m4
index 94863776..98a10416 100644
--- a/gl/m4/sys_socket_h.m4
+++ b/gl/m4/sys_socket_h.m4
@@ -1,12 +1,12 @@
-# sys_socket_h.m4 serial 23
-dnl Copyright (C) 2005-2013 Free Software Foundation, Inc.
+# sys_socket_h.m4 serial 29
+dnl Copyright (C) 2005-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl From Simon Josefsson.
 
-AC_DEFUN([gl_HEADER_SYS_SOCKET],
+AC_DEFUN_ONCE([gl_SYS_SOCKET_H],
 [
   AC_REQUIRE([gl_SYS_SOCKET_H_DEFAULTS])
   AC_REQUIRE([AC_CANONICAL_HOST])
@@ -22,6 +22,7 @@ AC_DEFUN([gl_HEADER_SYS_SOCKET],
       ;;
   esac
 
+  GL_GENERATE_SYS_SOCKET_H=false
   AC_CACHE_CHECK([whether <sys/socket.h> is self-contained],
     [gl_cv_header_sys_socket_h_selfcontained],
     [
@@ -44,7 +45,7 @@ AC_DEFUN([gl_HEADER_SYS_SOCKET],
             [gl_cv_header_sys_socket_h_shut=no])
         ])
       if test $gl_cv_header_sys_socket_h_shut = no; then
-        SYS_SOCKET_H='sys/socket.h'
+        GL_GENERATE_SYS_SOCKET_H=true
       fi
     fi
   fi
@@ -83,7 +84,7 @@ AC_DEFUN([gl_HEADER_SYS_SOCKET],
   fi
   if test $HAVE_STRUCT_SOCKADDR_STORAGE = 0 || test $HAVE_SA_FAMILY_T = 0 \
      || test $HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY = 0; then
-    SYS_SOCKET_H='sys/socket.h'
+    GL_GENERATE_SYS_SOCKET_H=true
   fi
   gl_PREREQ_SYS_H_WINSOCK2
 
@@ -95,6 +96,8 @@ AC_DEFUN([gl_HEADER_SYS_SOCKET],
 #include <sys/socket.h>
     ]], [socket connect accept bind getpeername getsockname getsockopt
     listen recv send recvfrom sendto setsockopt shutdown accept4])
+
+  AC_REQUIRE([AC_C_RESTRICT])
 ])
 
 AC_DEFUN([gl_PREREQ_SYS_H_SOCKET],
@@ -104,17 +107,11 @@ AC_DEFUN([gl_PREREQ_SYS_H_SOCKET],
   gl_CHECK_NEXT_HEADERS([sys/socket.h])
   if test $ac_cv_header_sys_socket_h = yes; then
     HAVE_SYS_SOCKET_H=1
-    HAVE_WS2TCPIP_H=0
   else
     HAVE_SYS_SOCKET_H=0
-    if test $ac_cv_header_ws2tcpip_h = yes; then
-      HAVE_WS2TCPIP_H=1
-    else
-      HAVE_WS2TCPIP_H=0
-    fi
   fi
   AC_SUBST([HAVE_SYS_SOCKET_H])
-  AC_SUBST([HAVE_WS2TCPIP_H])
+  gl_PREREQ_SYS_H_WS2TCPIP
 ])
 
 # Common prerequisites of the <sys/socket.h> replacement and of the
@@ -142,32 +139,65 @@ AC_DEFUN([gl_PREREQ_SYS_H_WINSOCK2],
   AC_SUBST([HAVE_WINSOCK2_H])
 ])
 
+# Common prerequisites of the <sys/socket.h> replacement and of the
+# <arpa/inet.h> replacement.
+# Sets and substitutes HAVE_WS2TCPIP_H.
+AC_DEFUN([gl_PREREQ_SYS_H_WS2TCPIP],
+[
+  AC_REQUIRE([gl_CHECK_SOCKET_HEADERS])
+  if test $ac_cv_header_sys_socket_h = yes; then
+    HAVE_WS2TCPIP_H=0
+  else
+    if test $ac_cv_header_ws2tcpip_h = yes; then
+      HAVE_WS2TCPIP_H=1
+    else
+      HAVE_WS2TCPIP_H=0
+    fi
+  fi
+  AC_SUBST([HAVE_WS2TCPIP_H])
+])
+
+# gl_SYS_SOCKET_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_SYS_SOCKET_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_SYS_SOCKET_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_SYS_SOCKET_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_SYS_SOCKET_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_SYS_SOCKET_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SOCKET])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CONNECT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ACCEPT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_BIND])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETPEERNAME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETSOCKNAME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETSOCKOPT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LISTEN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RECV])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SEND])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RECVFROM])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SENDTO])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SETSOCKOPT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SHUTDOWN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ACCEPT4])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_SYS_SOCKET_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_SYS_SOCKET_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_SYS_SOCKET_H_DEFAULTS],
 [
-  GNULIB_SOCKET=0;      AC_SUBST([GNULIB_SOCKET])
-  GNULIB_CONNECT=0;     AC_SUBST([GNULIB_CONNECT])
-  GNULIB_ACCEPT=0;      AC_SUBST([GNULIB_ACCEPT])
-  GNULIB_BIND=0;        AC_SUBST([GNULIB_BIND])
-  GNULIB_GETPEERNAME=0; AC_SUBST([GNULIB_GETPEERNAME])
-  GNULIB_GETSOCKNAME=0; AC_SUBST([GNULIB_GETSOCKNAME])
-  GNULIB_GETSOCKOPT=0;  AC_SUBST([GNULIB_GETSOCKOPT])
-  GNULIB_LISTEN=0;      AC_SUBST([GNULIB_LISTEN])
-  GNULIB_RECV=0;        AC_SUBST([GNULIB_RECV])
-  GNULIB_SEND=0;        AC_SUBST([GNULIB_SEND])
-  GNULIB_RECVFROM=0;    AC_SUBST([GNULIB_RECVFROM])
-  GNULIB_SENDTO=0;      AC_SUBST([GNULIB_SENDTO])
-  GNULIB_SETSOCKOPT=0;  AC_SUBST([GNULIB_SETSOCKOPT])
-  GNULIB_SHUTDOWN=0;    AC_SUBST([GNULIB_SHUTDOWN])
-  GNULIB_ACCEPT4=0;     AC_SUBST([GNULIB_ACCEPT4])
   HAVE_STRUCT_SOCKADDR_STORAGE=1; AC_SUBST([HAVE_STRUCT_SOCKADDR_STORAGE])
   HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY=1;
                         AC_SUBST([HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY])
diff --git a/gl/m4/sys_stat_h.m4 b/gl/m4/sys_stat_h.m4
new file mode 100644
index 00000000..ca57398a
--- /dev/null
+++ b/gl/m4/sys_stat_h.m4
@@ -0,0 +1,129 @@
+# sys_stat_h.m4 serial 42   -*- Autoconf -*-
+dnl Copyright (C) 2006-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Eric Blake.
+dnl Provide a GNU-like <sys/stat.h>.
+
+AC_DEFUN_ONCE([gl_SYS_STAT_H],
+[
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+
+  dnl Check for broken stat macros.
+  AC_REQUIRE([AC_HEADER_STAT])
+
+  gl_CHECK_NEXT_HEADERS([sys/stat.h])
+
+  dnl Ensure the type mode_t gets defined.
+  AC_REQUIRE([AC_TYPE_MODE_T])
+
+  dnl Whether to enable precise timestamps in 'struct stat'.
+  m4_ifdef([gl_WINDOWS_STAT_TIMESPEC], [
+    AC_REQUIRE([gl_WINDOWS_STAT_TIMESPEC])
+  ], [
+    WINDOWS_STAT_TIMESPEC=0
+  ])
+  AC_SUBST([WINDOWS_STAT_TIMESPEC])
+
+  dnl Whether to ensure that struct stat.st_size is 64-bit wide.
+  m4_ifdef([gl_LARGEFILE], [
+    AC_REQUIRE([gl_LARGEFILE])
+  ], [
+    WINDOWS_64_BIT_ST_SIZE=0
+  ])
+  AC_SUBST([WINDOWS_64_BIT_ST_SIZE])
+
+  dnl Define types that are supposed to be defined in <sys/types.h> or
+  dnl <sys/stat.h>.
+  AC_CHECK_TYPE([nlink_t], [],
+    [AC_DEFINE([nlink_t], [int],
+       [Define to the type of st_nlink in struct stat, or a supertype.])],
+    [#include <sys/types.h>
+     #include <sys/stat.h>])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <sys/stat.h>
+    ]], [chmod fchmodat fstat fstatat futimens getumask lchmod lstat
+    mkdirat mkfifo mkfifoat mknod mknodat stat utimensat])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+])
+
+# gl_SYS_STAT_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
+AC_DEFUN([gl_SYS_STAT_MODULE_INDICATOR],
+[
+  dnl Ensure to expand the default settings once only.
+  gl_SYS_STAT_H_REQUIRE_DEFAULTS
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_SYS_STAT_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_SYS_STAT_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_UNISTD_H_REQUIRE_DEFAULTS dnl for REPLACE_FCHDIR
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CHMOD])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FCHMODAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FSTAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FSTATAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FUTIMENS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETUMASK])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LCHMOD])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LSTAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MKDIR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MKDIRAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MKFIFO])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MKFIFOAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MKNOD])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MKNODAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_UTIMENSAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_OVERRIDES_STRUCT_STAT])
+    dnl Support Microsoft deprecated alias function names by default.
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_CHMOD], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_MKDIR], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_UMASK], [1])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_SYS_STAT_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+])
+
+AC_DEFUN([gl_SYS_STAT_H_DEFAULTS],
+[
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_FCHMODAT=1;      AC_SUBST([HAVE_FCHMODAT])
+  HAVE_FSTATAT=1;       AC_SUBST([HAVE_FSTATAT])
+  HAVE_FUTIMENS=1;      AC_SUBST([HAVE_FUTIMENS])
+  HAVE_GETUMASK=1;      AC_SUBST([HAVE_GETUMASK])
+  HAVE_LCHMOD=1;        AC_SUBST([HAVE_LCHMOD])
+  HAVE_LSTAT=1;         AC_SUBST([HAVE_LSTAT])
+  HAVE_MKDIRAT=1;       AC_SUBST([HAVE_MKDIRAT])
+  HAVE_MKFIFO=1;        AC_SUBST([HAVE_MKFIFO])
+  HAVE_MKFIFOAT=1;      AC_SUBST([HAVE_MKFIFOAT])
+  HAVE_MKNOD=1;         AC_SUBST([HAVE_MKNOD])
+  HAVE_MKNODAT=1;       AC_SUBST([HAVE_MKNODAT])
+  HAVE_UTIMENSAT=1;     AC_SUBST([HAVE_UTIMENSAT])
+  REPLACE_CHMOD=0;      AC_SUBST([REPLACE_CHMOD])
+  REPLACE_FCHMODAT=0;   AC_SUBST([REPLACE_FCHMODAT])
+  REPLACE_FSTAT=0;      AC_SUBST([REPLACE_FSTAT])
+  REPLACE_FSTATAT=0;    AC_SUBST([REPLACE_FSTATAT])
+  REPLACE_FUTIMENS=0;   AC_SUBST([REPLACE_FUTIMENS])
+  REPLACE_LSTAT=0;      AC_SUBST([REPLACE_LSTAT])
+  REPLACE_MKDIR=0;      AC_SUBST([REPLACE_MKDIR])
+  REPLACE_MKFIFO=0;     AC_SUBST([REPLACE_MKFIFO])
+  REPLACE_MKFIFOAT=0;   AC_SUBST([REPLACE_MKFIFOAT])
+  REPLACE_MKNOD=0;      AC_SUBST([REPLACE_MKNOD])
+  REPLACE_MKNODAT=0;    AC_SUBST([REPLACE_MKNODAT])
+  REPLACE_STAT=0;       AC_SUBST([REPLACE_STAT])
+  REPLACE_UTIMENSAT=0;  AC_SUBST([REPLACE_UTIMENSAT])
+])
diff --git a/gl/m4/sys_types_h.m4 b/gl/m4/sys_types_h.m4
index d15c1b37..627671fb 100644
--- a/gl/m4/sys_types_h.m4
+++ b/gl/m4/sys_types_h.m4
@@ -1,5 +1,5 @@
-# sys_types_h.m4 serial 5
-dnl Copyright (C) 2011-2013 Free Software Foundation, Inc.
+# sys_types_h.m4 serial 13
+dnl Copyright (C) 2011-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -7,6 +7,10 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN_ONCE([gl_SYS_TYPES_H],
 [
   AC_REQUIRE([gl_SYS_TYPES_H_DEFAULTS])
+
+  dnl Use sane struct stat types in OpenVMS 8.2 and later.
+  AC_DEFINE([_USE_STD_STAT], 1, [For standard stat data types on VMS.])
+
   gl_NEXT_HEADERS([sys/types.h])
 
   dnl Ensure the type pid_t gets defined.
@@ -17,8 +21,50 @@ AC_DEFUN_ONCE([gl_SYS_TYPES_H],
 
   dnl Whether to override the 'off_t' type.
   AC_REQUIRE([gl_TYPE_OFF_T])
+
+  dnl Whether to override the 'dev_t' and 'ino_t' types.
+  m4_ifdef([gl_WINDOWS_STAT_INODES], [
+    AC_REQUIRE([gl_WINDOWS_STAT_INODES])
+  ], [
+    WINDOWS_STAT_INODES=0
+  ])
+  AC_SUBST([WINDOWS_STAT_INODES])
+])
+
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_SYS_TYPES_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_SYS_TYPE_H_MODULE_INDICATOR_DEFAULTS], [
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_SYS_TYPE_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_SYS_TYPES_H_DEFAULTS])
 ])
 
 AC_DEFUN([gl_SYS_TYPES_H_DEFAULTS],
 [
 ])
+
+# This works around a buggy version in autoconf <= 2.69.
+# See <https://lists.gnu.org/r/autoconf/2016-08/msg00014.html>
+# The 2.70 version isn't quoted properly, so override it too.
+
+m4_version_prereq([2.70.1], [], [
+
+m4_undefine([AC_HEADER_MAJOR])
+AC_DEFUN([AC_HEADER_MAJOR],
+[AC_CHECK_HEADERS_ONCE([sys/types.h])
+AC_CHECK_HEADER([sys/mkdev.h],
+                [AC_DEFINE([MAJOR_IN_MKDEV], [1],
+                           [Define to 1 if `major', `minor', and `makedev' are
+                            declared in <mkdev.h>.])])
+if test $ac_cv_header_sys_mkdev_h = no; then
+  AC_CHECK_HEADER([sys/sysmacros.h],
+                  [AC_DEFINE([MAJOR_IN_SYSMACROS], [1],
+                             [Define to 1 if `major', `minor', and `makedev'
+                              are declared in <sysmacros.h>.])])
+fi
+])# AC_HEADER_MAJOR
+
+])
diff --git a/gl/m4/sys_uio_h.m4 b/gl/m4/sys_uio_h.m4
index c75cbbd0..93a65d26 100644
--- a/gl/m4/sys_uio_h.m4
+++ b/gl/m4/sys_uio_h.m4
@@ -1,10 +1,10 @@
-# sys_uio_h.m4 serial 1
-dnl Copyright (C) 2011-2013 Free Software Foundation, Inc.
+# sys_uio_h.m4 serial 3
+dnl Copyright (C) 2011-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-AC_DEFUN([gl_HEADER_SYS_UIO],
+AC_DEFUN_ONCE([gl_SYS_UIO_H],
 [
   AC_REQUIRE([gl_SYS_UIO_H_DEFAULTS])
   dnl <sys/uio.h> is always overridden, because of GNULIB_POSIXCHECK.
@@ -17,15 +17,30 @@ AC_DEFUN([gl_HEADER_SYS_UIO],
   AC_SUBST([HAVE_SYS_UIO_H])
 ])
 
+# gl_SYS_UIO_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_SYS_UIO_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_SYS_UIO_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_SYS_UIO_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_SYS_UIO_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_SYS_UIO_H_MODULE_INDICATOR_DEFAULTS], [
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_SYS_UIO_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_SYS_UIO_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_SYS_UIO_H_DEFAULTS],
 [
 ])
diff --git a/gl/m4/threadlib.m4 b/gl/m4/threadlib.m4
index 26bdeb58..b536b047 100644
--- a/gl/m4/threadlib.m4
+++ b/gl/m4/threadlib.m4
@@ -1,11 +1,390 @@
-# threadlib.m4 serial 10 (gettext-0.18.2)
-dnl Copyright (C) 2005-2013 Free Software Foundation, Inc.
+# threadlib.m4 serial 32a
+dnl Copyright (C) 2005-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl From Bruno Haible.
 
+AC_PREREQ([2.60])
+
+dnl The general structure of the multithreading modules in gnulib is that we
+dnl have three set of modules:
+dnl
+dnl   * POSIX API:
+dnl     pthread, which combines
+dnl       pthread-h
+dnl       pthread-thread
+dnl       pthread-once
+dnl       pthread-mutex
+dnl       pthread-rwlock
+dnl       pthread-cond
+dnl       pthread-tss
+dnl       pthread-spin
+dnl     sched_yield
+dnl
+dnl   * ISO C API:
+dnl     threads, which combines
+dnl       threads-h
+dnl       thrd
+dnl       mtx
+dnl       cnd
+dnl       tss
+dnl
+dnl   * Gnulib API, with an implementation that can be chosen at configure
+dnl     time through the option --enable-threads=...
+dnl       thread
+dnl       lock
+dnl       cond
+dnl       tls
+dnl       yield
+dnl
+dnl They are independent, except for the fact that
+dnl   - the implementation of the ISO C API may use the POSIX (or some other
+dnl     platform dependent) API,
+dnl   - the implementation of the Gnulib API may use the POSIX or ISO C or
+dnl     some other platform dependent API, depending on the --enable-threads
+dnl     option.
+dnl
+dnl This file contains macros for all of these APIs!
+
+dnl ============================================================================
+dnl Macros for all thread APIs
+
+AC_DEFUN([gl_ANYTHREADLIB_EARLY],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  if test -z "$gl_anythreadlib_early_done"; then
+    case "$host_os" in
+      osf*)
+        # On OSF/1, the compiler needs the flag -D_REENTRANT so that it
+        # groks <pthread.h>. cc also understands the flag -pthread, but
+        # we don't use it because 1. gcc-2.95 doesn't understand -pthread,
+        # 2. putting a flag into CPPFLAGS that has an effect on the linker
+        # causes the AC_LINK_IFELSE test below to succeed unexpectedly,
+        # leading to wrong values of LIBTHREAD and LTLIBTHREAD.
+        CPPFLAGS="$CPPFLAGS -D_REENTRANT"
+        ;;
+    esac
+    # Some systems optimize for single-threaded programs by default, and
+    # need special flags to disable these optimizations. For example, the
+    # definition of 'errno' in <errno.h>.
+    case "$host_os" in
+      aix* | freebsd*) CPPFLAGS="$CPPFLAGS -D_THREAD_SAFE" ;;
+      solaris*) CPPFLAGS="$CPPFLAGS -D_REENTRANT" ;;
+    esac
+    gl_anythreadlib_early_done=done
+  fi
+])
+
+dnl Checks whether the compiler and linker support weak declarations of symbols.
+
+AC_DEFUN([gl_WEAK_SYMBOLS],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CACHE_CHECK([whether imported symbols can be declared weak],
+    [gl_cv_have_weak],
+    [case "$host_os" in
+       cygwin*)
+         dnl On Cygwin 3.2.0 with gcc 10.2, the test below would succeed, but
+         dnl programs that use pthread_in_use() with weak symbol references
+         dnl crash miserably at runtime.
+         gl_cv_have_weak="guessing no"
+         ;;
+       *)
+         gl_cv_have_weak=no
+         dnl First, test whether the compiler accepts it syntactically.
+         AC_LINK_IFELSE(
+           [AC_LANG_PROGRAM(
+              [[extern void xyzzy ();
+#pragma weak xyzzy]],
+              [[xyzzy();]])],
+           [gl_cv_have_weak=maybe])
+         if test $gl_cv_have_weak = maybe; then
+           dnl Second, test whether it actually works. On Cygwin 1.7.2, with
+           dnl gcc 4.3, symbols declared weak always evaluate to the address 0.
+           AC_RUN_IFELSE(
+             [AC_LANG_SOURCE([[
+#include <stdio.h>
+#pragma weak fputs
+int main ()
+{
+  return (fputs == NULL);
+}]])],
+             [gl_cv_have_weak=yes],
+             [gl_cv_have_weak=no],
+             [dnl When cross-compiling, assume that only ELF platforms support
+              dnl weak symbols.
+              AC_EGREP_CPP([Extensible Linking Format],
+                [#ifdef __ELF__
+                 Extensible Linking Format
+                 #endif
+                ],
+                [gl_cv_have_weak="guessing yes"],
+                [gl_cv_have_weak="guessing no"])
+             ])
+         fi
+         ;;
+     esac
+     dnl But when linking statically, weak symbols don't work.
+     case " $LDFLAGS " in
+       *" -static "*) gl_cv_have_weak=no ;;
+     esac
+     dnl Test for a bug in FreeBSD 11: A link error occurs when using a weak
+     dnl symbol and linking against a shared library that has a dependency on
+     dnl the shared library that defines the symbol.
+     case "$gl_cv_have_weak" in
+       *yes)
+         case "$host_os" in
+           freebsd* | dragonfly* | midnightbsd*)
+             : > conftest1.c
+             $CC $CPPFLAGS $CFLAGS $LDFLAGS -fPIC -shared -o libempty.so conftest1.c -lpthread >&AS_MESSAGE_LOG_FD 2>&1
+             cat <<EOF > conftest2.c
+#include <pthread.h>
+#pragma weak pthread_mutexattr_gettype
+int main ()
+{
+  return (pthread_mutexattr_gettype != NULL);
+}
+EOF
+             $CC $CPPFLAGS $CFLAGS $LDFLAGS -o conftest conftest2.c libempty.so >&AS_MESSAGE_LOG_FD 2>&1 \
+               || gl_cv_have_weak=no
+             rm -f conftest1.c libempty.so conftest2.c conftest
+             ;;
+         esac
+         ;;
+     esac
+    ])
+  case "$gl_cv_have_weak" in
+    *yes)
+      AC_DEFINE([HAVE_WEAK_SYMBOLS], [1],
+        [Define to 1 if the compiler and linker support weak declarations of symbols.])
+      ;;
+  esac
+])
+
+dnl ============================================================================
+dnl Macros for the POSIX API
+
+dnl gl_PTHREADLIB
+dnl -------------
+dnl Tests for the libraries needs for using the POSIX threads API.
+dnl Sets the variable LIBPTHREAD to the linker options for use in a Makefile.
+dnl Sets the variable LIBPMULTITHREAD, for programs that really need
+dnl multithread functionality. The difference between LIBPTHREAD and
+dnl LIBPMULTITHREAD is that on platforms supporting weak symbols, typically
+dnl LIBPTHREAD is empty whereas LIBPMULTITHREAD is not.
+dnl Sets the variable LIB_SCHED_YIELD to the linker options needed to use the
+dnl sched_yield() function.
+dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
+dnl multithread-safe programs.
+dnl Defines the C macro HAVE_PTHREAD_API if (at least parts of) the POSIX
+dnl threads API is available.
+
+dnl The guts of gl_PTHREADLIB. Needs to be expanded only once.
+
+AC_DEFUN([gl_PTHREADLIB_BODY],
+[
+  AC_REQUIRE([gl_ANYTHREADLIB_EARLY])
+  if test -z "$gl_pthreadlib_body_done"; then
+    gl_pthread_api=no
+    LIBPTHREAD=
+    LIBPMULTITHREAD=
+    # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that
+    # it groks <pthread.h>. It's added above, in gl_ANYTHREADLIB_EARLY.
+    AC_CHECK_HEADER([pthread.h],
+      [gl_have_pthread_h=yes], [gl_have_pthread_h=no])
+    if test "$gl_have_pthread_h" = yes; then
+      # Other possible tests:
+      #   -lpthreads (FSU threads, PCthreads)
+      #   -lgthreads
+      # Test whether both pthread_mutex_lock and pthread_mutexattr_init exist
+      # in libc. IRIX 6.5 has the first one in both libc and libpthread, but
+      # the second one only in libpthread, and lock.c needs it.
+      #
+      # If -pthread works, prefer it to -lpthread, since Ubuntu 14.04
+      # needs -pthread for some reason.  See:
+      # https://lists.gnu.org/r/bug-gnulib/2014-09/msg00023.html
+      save_LIBS=$LIBS
+      for gl_pthread in '' '-pthread'; do
+        LIBS="$LIBS $gl_pthread"
+        AC_LINK_IFELSE(
+          [AC_LANG_PROGRAM(
+             [[#include <pthread.h>
+               pthread_mutex_t m;
+               pthread_mutexattr_t ma;
+             ]],
+             [[pthread_mutex_lock (&m);
+               pthread_mutexattr_init (&ma);]])],
+          [gl_pthread_api=yes
+           LIBPTHREAD=$gl_pthread
+           LIBPMULTITHREAD=$gl_pthread])
+        LIBS=$save_LIBS
+        test $gl_pthread_api = yes && break
+      done
+      echo "$as_me:__oline__: gl_pthread_api=$gl_pthread_api" >&AS_MESSAGE_LOG_FD
+      echo "$as_me:__oline__: LIBPTHREAD=$LIBPTHREAD" >&AS_MESSAGE_LOG_FD
+
+      gl_pthread_in_glibc=no
+      # On Linux with glibc >= 2.34, libc contains the fully functional
+      # pthread functions.
+      case "$host_os" in
+        linux*)
+          AC_EGREP_CPP([Lucky user],
+            [#include <features.h>
+             #ifdef __GNU_LIBRARY__
+              #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 34) || (__GLIBC__ > 2)
+               Lucky user
+              #endif
+             #endif
+            ],
+            [gl_pthread_in_glibc=yes],
+            [])
+          ;;
+      esac
+      echo "$as_me:__oline__: gl_pthread_in_glibc=$gl_pthread_in_glibc" >&AS_MESSAGE_LOG_FD
+
+      # Test for libpthread by looking for pthread_kill. (Not pthread_self,
+      # since it is defined as a macro on OSF/1.)
+      if test $gl_pthread_api = yes && test -z "$LIBPTHREAD"; then
+        # The program links fine without libpthread. But it may actually
+        # need to link with libpthread in order to create multiple threads.
+        AC_CHECK_LIB([pthread], [pthread_kill],
+          [if test $gl_pthread_in_glibc = yes; then
+             LIBPMULTITHREAD=
+           else
+             LIBPMULTITHREAD=-lpthread
+             # On Solaris and HP-UX, most pthread functions exist also in libc.
+             # Therefore pthread_in_use() needs to actually try to create a
+             # thread: pthread_create from libc will fail, whereas
+             # pthread_create will actually create a thread.
+             # On Solaris 10 or newer, this test is no longer needed, because
+             # libc contains the fully functional pthread functions.
+             case "$host_os" in
+changequote(,)dnl
+               solaris | solaris2.[1-9] | solaris2.[1-9].* | hpux*)
+changequote([,])dnl
+                 AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], [1],
+                   [Define if the pthread_in_use() detection is hard.])
+             esac
+           fi
+          ])
+      elif test $gl_pthread_api != yes; then
+        # Some library is needed. Try libpthread and libc_r.
+        AC_CHECK_LIB([pthread], [pthread_kill],
+          [gl_pthread_api=yes
+           LIBPTHREAD=-lpthread
+           LIBPMULTITHREAD=-lpthread])
+        if test $gl_pthread_api != yes; then
+          # For FreeBSD 4.
+          AC_CHECK_LIB([c_r], [pthread_kill],
+            [gl_pthread_api=yes
+             LIBPTHREAD=-lc_r
+             LIBPMULTITHREAD=-lc_r])
+        fi
+      fi
+      echo "$as_me:__oline__: LIBPMULTITHREAD=$LIBPMULTITHREAD" >&AS_MESSAGE_LOG_FD
+    fi
+    AC_MSG_CHECKING([whether POSIX threads API is available])
+    AC_MSG_RESULT([$gl_pthread_api])
+    AC_SUBST([LIBPTHREAD])
+    AC_SUBST([LIBPMULTITHREAD])
+    if test $gl_pthread_api = yes; then
+      AC_DEFINE([HAVE_PTHREAD_API], [1],
+        [Define if you have the <pthread.h> header and the POSIX threads API.])
+    fi
+
+    dnl On some systems, sched_yield is in librt, rather than in libpthread.
+    AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[#include <sched.h>]],
+         [[sched_yield ();]])],
+      [LIB_SCHED_YIELD=
+      ],
+      [dnl Solaris 7...10 has sched_yield in librt, not in libpthread or libc.
+       AC_CHECK_LIB([rt], [sched_yield], [LIB_SCHED_YIELD=-lrt],
+         [dnl Solaris 2.5.1, 2.6 has sched_yield in libposix4, not librt.
+          AC_CHECK_LIB([posix4], [sched_yield], [LIB_SCHED_YIELD=-lposix4])])
+      ])
+    AC_SUBST([LIB_SCHED_YIELD])
+
+    gl_pthreadlib_body_done=done
+  fi
+])
+
+AC_DEFUN([gl_PTHREADLIB],
+[
+  AC_REQUIRE([gl_ANYTHREADLIB_EARLY])
+  gl_PTHREADLIB_BODY
+])
+
+dnl ============================================================================
+dnl Macros for the ISO C API
+
+dnl gl_STDTHREADLIB
+dnl ---------------
+dnl Tests for the libraries needs for using the ISO C threads API.
+dnl Sets the variable LIBSTDTHREAD to the linker options for use in a Makefile.
+dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
+dnl multithread-safe programs.
+dnl Defines the C macro HAVE_THREADS_H if (at least parts of) the ISO C threads
+dnl API is available.
+
+dnl The guts of gl_STDTHREADLIB. Needs to be expanded only once.
+
+AC_DEFUN([gl_STDTHREADLIB_BODY],
+[
+  AC_REQUIRE([gl_ANYTHREADLIB_EARLY])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  if test -z "$gl_stdthreadlib_body_done"; then
+    AC_CHECK_HEADERS_ONCE([threads.h])
+
+    case "$host_os" in
+      mingw*)
+        LIBSTDTHREAD=
+        ;;
+      *)
+        gl_PTHREADLIB_BODY
+        if test $ac_cv_header_threads_h = yes; then
+          dnl glibc >= 2.29 has thrd_create in libpthread.
+          dnl FreeBSD >= 10 has thrd_create in libstdthreads; this library depends
+          dnl on libpthread (for the symbol 'pthread_mutexattr_gettype').
+          dnl glibc >= 2.34, AIX >= 7.1, and Solaris >= 11.4 have thrd_create in
+          dnl libc.
+          AC_CHECK_FUNCS([thrd_create])
+          if test $ac_cv_func_thrd_create = yes; then
+            LIBSTDTHREAD=
+          else
+            AC_CHECK_LIB([stdthreads], [thrd_create], [
+              LIBSTDTHREAD='-lstdthreads -lpthread'
+            ], [
+              dnl Guess that thrd_create is in libpthread.
+              LIBSTDTHREAD="$LIBPMULTITHREAD"
+            ])
+          fi
+        else
+          dnl Libraries needed by thrd.c, mtx.c, cnd.c, tss.c.
+          LIBSTDTHREAD="$LIBPMULTITHREAD $LIB_SCHED_YIELD"
+        fi
+        ;;
+    esac
+    AC_SUBST([LIBSTDTHREAD])
+
+    AC_MSG_CHECKING([whether ISO C threads API is available])
+    AC_MSG_RESULT([$ac_cv_header_threads_h])
+    gl_stdthreadlib_body_done=done
+  fi
+])
+
+AC_DEFUN([gl_STDTHREADLIB],
+[
+  AC_REQUIRE([gl_ANYTHREADLIB_EARLY])
+  gl_STDTHREADLIB_BODY
+])
+
+dnl ============================================================================
+dnl Macros for the Gnulib API
+
 dnl gl_THREADLIB
 dnl ------------
 dnl Tests for a multithreading library to be used.
@@ -14,17 +393,25 @@ dnl (it must be placed before the invocation of gl_THREADLIB_EARLY!), then the
 dnl default is 'no', otherwise it is system dependent. In both cases, the user
 dnl can change the choice through the options --enable-threads=choice or
 dnl --disable-threads.
-dnl Defines at most one of the macros USE_POSIX_THREADS, USE_SOLARIS_THREADS,
-dnl USE_PTH_THREADS, USE_WINDOWS_THREADS
+dnl Defines at most one of the macros USE_ISOC_THREADS, USE_POSIX_THREADS,
+dnl USE_ISOC_AND_POSIX_THREADS, USE_WINDOWS_THREADS.
+dnl The choice --enable-threads=isoc+posix is available only on platforms that
+dnl have both the ISO C and the POSIX threads APIs. It has the effect of using
+dnl the ISO C API for most things and the POSIX API only for creating and
+dnl controlling threads (because there is no equivalent to pthread_atfork in
+dnl the ISO C API).
 dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use
 dnl in a Makefile (LIBTHREAD for use without libtool, LTLIBTHREAD for use with
 dnl libtool).
 dnl Sets the variables LIBMULTITHREAD and LTLIBMULTITHREAD similarly, for
 dnl programs that really need multithread functionality. The difference
 dnl between LIBTHREAD and LIBMULTITHREAD is that on platforms supporting weak
-dnl symbols, typically LIBTHREAD="" whereas LIBMULTITHREAD="-lpthread".
+dnl symbols, typically LIBTHREAD is empty whereas LIBMULTITHREAD is not.
 dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
 dnl multithread-safe programs.
+dnl Since support for GNU pth was removed, $LTLIBTHREAD and $LIBTHREAD have the
+dnl same value, and similarly $LTLIBMULTITHREAD and $LIBMULTITHREAD have the
+dnl same value. Only system libraries are needed.
 
 AC_DEFUN([gl_THREADLIB_EARLY],
 [
@@ -43,18 +430,15 @@ AC_DEFUN([gl_THREADLIB_EARLY_BODY],
 
   AC_REQUIRE([AC_CANONICAL_HOST])
   dnl _GNU_SOURCE is needed for pthread_rwlock_t on glibc systems.
-  dnl AC_USE_SYSTEM_EXTENSIONS was introduced in autoconf 2.60 and obsoletes
-  dnl AC_GNU_SOURCE.
-  m4_ifdef([AC_USE_SYSTEM_EXTENSIONS],
-    [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])],
-    [AC_REQUIRE([AC_GNU_SOURCE])])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
   dnl Check for multithreading.
   m4_ifdef([gl_THREADLIB_DEFAULT_NO],
     [m4_divert_text([DEFAULTS], [gl_use_threads_default=no])],
     [m4_divert_text([DEFAULTS], [gl_use_threads_default=])])
+  m4_divert_text([DEFAULTS], [gl_use_winpthreads_default=])
   AC_ARG_ENABLE([threads],
-AC_HELP_STRING([--enable-threads={posix|solaris|pth|windows}], [specify multithreading API])m4_ifdef([gl_THREADLIB_DEFAULT_NO], [], [
-AC_HELP_STRING([--disable-threads], [build without multithread safety])]),
+AS_HELP_STRING([--enable-threads={isoc|posix|isoc+posix|windows}], [specify multithreading API])m4_ifdef([gl_THREADLIB_DEFAULT_NO], [], [
+AS_HELP_STRING([--disable-threads], [build without multithread safety])]),
     [gl_use_threads=$enableval],
     [if test -n "$gl_use_threads_default"; then
        gl_use_threads="$gl_use_threads_default"
@@ -64,41 +448,35 @@ changequote(,)dnl
          dnl Disable multithreading by default on OSF/1, because it interferes
          dnl with fork()/exec(): When msgexec is linked with -lpthread, its
          dnl child process gets an endless segmentation fault inside execvp().
+         osf*) gl_use_threads=no ;;
          dnl Disable multithreading by default on Cygwin 1.5.x, because it has
          dnl bugs that lead to endless loops or crashes. See
-         dnl <http://cygwin.com/ml/cygwin/2009-08/msg00283.html>.
-         osf*) gl_use_threads=no ;;
+         dnl <https://cygwin.com/ml/cygwin/2009-08/msg00283.html>.
          cygwin*)
                case `uname -r` in
                  1.[0-5].*) gl_use_threads=no ;;
                  *)         gl_use_threads=yes ;;
                esac
                ;;
+         dnl Obey gl_AVOID_WINPTHREAD on mingw.
+         mingw*)
+               case "$gl_use_winpthreads_default" in
+                 yes) gl_use_threads=posix ;;
+                 no)  gl_use_threads=windows ;;
+                 *)   gl_use_threads=yes ;;
+               esac
+               ;;
          *)    gl_use_threads=yes ;;
        esac
 changequote([,])dnl
      fi
     ])
-  if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
-    # For using <pthread.h>:
-    case "$host_os" in
-      osf*)
-        # On OSF/1, the compiler needs the flag -D_REENTRANT so that it
-        # groks <pthread.h>. cc also understands the flag -pthread, but
-        # we don't use it because 1. gcc-2.95 doesn't understand -pthread,
-        # 2. putting a flag into CPPFLAGS that has an effect on the linker
-        # causes the AC_LINK_IFELSE test below to succeed unexpectedly,
-        # leading to wrong values of LIBTHREAD and LTLIBTHREAD.
-        CPPFLAGS="$CPPFLAGS -D_REENTRANT"
-        ;;
-    esac
-    # Some systems optimize for single-threaded programs by default, and
-    # need special flags to disable these optimizations. For example, the
-    # definition of 'errno' in <errno.h>.
-    case "$host_os" in
-      aix* | freebsd*) CPPFLAGS="$CPPFLAGS -D_THREAD_SAFE" ;;
-      solaris*) CPPFLAGS="$CPPFLAGS -D_REENTRANT" ;;
-    esac
+  if test "$gl_use_threads" = yes \
+     || test "$gl_use_threads" = isoc \
+     || test "$gl_use_threads" = posix \
+     || test "$gl_use_threads" = isoc+posix; then
+    # For using <threads.h> or <pthread.h>:
+    gl_ANYTHREADLIB_EARLY
   fi
 ])
 
@@ -114,168 +492,69 @@ AC_DEFUN([gl_THREADLIB_BODY],
   LTLIBMULTITHREAD=
   if test "$gl_use_threads" != no; then
     dnl Check whether the compiler and linker support weak declarations.
-    AC_CACHE_CHECK([whether imported symbols can be declared weak],
-      [gl_cv_have_weak],
-      [gl_cv_have_weak=no
-       dnl First, test whether the compiler accepts it syntactically.
-       AC_LINK_IFELSE(
-         [AC_LANG_PROGRAM(
-            [[extern void xyzzy ();
-#pragma weak xyzzy]],
-            [[xyzzy();]])],
-         [gl_cv_have_weak=maybe])
-       if test $gl_cv_have_weak = maybe; then
-         dnl Second, test whether it actually works. On Cygwin 1.7.2, with
-         dnl gcc 4.3, symbols declared weak always evaluate to the address 0.
-         AC_RUN_IFELSE(
-           [AC_LANG_SOURCE([[
-#include <stdio.h>
-#pragma weak fputs
-int main ()
-{
-  return (fputs == NULL);
-}]])],
-           [gl_cv_have_weak=yes],
-           [gl_cv_have_weak=no],
-           [dnl When cross-compiling, assume that only ELF platforms support
-            dnl weak symbols.
-            AC_EGREP_CPP([Extensible Linking Format],
-              [#ifdef __ELF__
-               Extensible Linking Format
-               #endif
-              ],
-              [gl_cv_have_weak="guessing yes"],
-              [gl_cv_have_weak="guessing no"])
-           ])
-       fi
-      ])
-    if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
-      # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that
-      # it groks <pthread.h>. It's added above, in gl_THREADLIB_EARLY_BODY.
-      AC_CHECK_HEADER([pthread.h],
-        [gl_have_pthread_h=yes], [gl_have_pthread_h=no])
-      if test "$gl_have_pthread_h" = yes; then
-        # Other possible tests:
-        #   -lpthreads (FSU threads, PCthreads)
-        #   -lgthreads
-        gl_have_pthread=
-        # Test whether both pthread_mutex_lock and pthread_mutexattr_init exist
-        # in libc. IRIX 6.5 has the first one in both libc and libpthread, but
-        # the second one only in libpthread, and lock.c needs it.
-        AC_LINK_IFELSE(
-          [AC_LANG_PROGRAM(
-             [[#include <pthread.h>]],
-             [[pthread_mutex_lock((pthread_mutex_t*)0);
-               pthread_mutexattr_init((pthread_mutexattr_t*)0);]])],
-          [gl_have_pthread=yes])
-        # Test for libpthread by looking for pthread_kill. (Not pthread_self,
-        # since it is defined as a macro on OSF/1.)
-        if test -n "$gl_have_pthread"; then
-          # The program links fine without libpthread. But it may actually
-          # need to link with libpthread in order to create multiple threads.
-          AC_CHECK_LIB([pthread], [pthread_kill],
-            [LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread
-             # On Solaris and HP-UX, most pthread functions exist also in libc.
-             # Therefore pthread_in_use() needs to actually try to create a
-             # thread: pthread_create from libc will fail, whereas
-             # pthread_create will actually create a thread.
-             case "$host_os" in
-               solaris* | hpux*)
-                 AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], [1],
-                   [Define if the pthread_in_use() detection is hard.])
-             esac
-            ])
+    gl_WEAK_SYMBOLS
+    if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
+      dnl If we use weak symbols to implement pthread_in_use / pth_in_use /
+      dnl thread_in_use, we also need to test whether the ISO C 11 thrd_create
+      dnl facility is in use.
+      AC_CHECK_HEADERS_ONCE([threads.h])
+      :
+    fi
+    if test "$gl_use_threads" = isoc || test "$gl_use_threads" = isoc+posix; then
+      AC_CHECK_HEADERS_ONCE([threads.h])
+      gl_have_isoc_threads="$ac_cv_header_threads_h"
+    fi
+    if test "$gl_use_threads" = yes \
+       || test "$gl_use_threads" = posix \
+       || test "$gl_use_threads" = isoc+posix; then
+      gl_PTHREADLIB_BODY
+      LIBTHREAD=$LIBPTHREAD LTLIBTHREAD=$LIBPTHREAD
+      LIBMULTITHREAD=$LIBPMULTITHREAD LTLIBMULTITHREAD=$LIBPMULTITHREAD
+      if test $gl_pthread_api = yes; then
+        if test "$gl_use_threads" = isoc+posix && test "$gl_have_isoc_threads" = yes; then
+          gl_threads_api='isoc+posix'
+          AC_DEFINE([USE_ISOC_AND_POSIX_THREADS], [1],
+            [Define if the combination of the ISO C and POSIX multithreading APIs can be used.])
+          LIBTHREAD= LTLIBTHREAD=
         else
-          # Some library is needed. Try libpthread and libc_r.
-          AC_CHECK_LIB([pthread], [pthread_kill],
-            [gl_have_pthread=yes
-             LIBTHREAD=-lpthread LTLIBTHREAD=-lpthread
-             LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread])
-          if test -z "$gl_have_pthread"; then
-            # For FreeBSD 4.
-            AC_CHECK_LIB([c_r], [pthread_kill],
-              [gl_have_pthread=yes
-               LIBTHREAD=-lc_r LTLIBTHREAD=-lc_r
-               LIBMULTITHREAD=-lc_r LTLIBMULTITHREAD=-lc_r])
-          fi
-        fi
-        if test -n "$gl_have_pthread"; then
           gl_threads_api=posix
           AC_DEFINE([USE_POSIX_THREADS], [1],
             [Define if the POSIX multithreading library can be used.])
-          if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
+          if test -z "$LIBMULTITHREAD" && test -z "$LTLIBMULTITHREAD"; then
+            AC_DEFINE([USE_POSIX_THREADS_FROM_LIBC], [1],
+              [Define if references to the POSIX multithreading library are satisfied by libc.])
+          else
             if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
               AC_DEFINE([USE_POSIX_THREADS_WEAK], [1],
                 [Define if references to the POSIX multithreading library should be made weak.])
-              LIBTHREAD=
-              LTLIBTHREAD=
+              LIBTHREAD= LTLIBTHREAD=
+            else
+              case "$host_os" in
+                freebsd* | dragonfly* | midnightbsd*)
+                  if test "x$LIBTHREAD" != "x$LIBMULTITHREAD"; then
+                    dnl If weak symbols can't tell whether pthread_create(), pthread_key_create()
+                    dnl etc. will succeed, we need a runtime test.
+                    AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], [1],
+                      [Define if the pthread_in_use() detection is hard.])
+                  fi
+                  ;;
+              esac
             fi
           fi
         fi
       fi
     fi
-    if test -z "$gl_have_pthread"; then
-      if test "$gl_use_threads" = yes || test "$gl_use_threads" = solaris; then
-        gl_have_solaristhread=
-        gl_save_LIBS="$LIBS"
-        LIBS="$LIBS -lthread"
-        AC_LINK_IFELSE(
-          [AC_LANG_PROGRAM(
-             [[
-#include <thread.h>
-#include <synch.h>
-             ]],
-             [[thr_self();]])],
-          [gl_have_solaristhread=yes])
-        LIBS="$gl_save_LIBS"
-        if test -n "$gl_have_solaristhread"; then
-          gl_threads_api=solaris
-          LIBTHREAD=-lthread
-          LTLIBTHREAD=-lthread
-          LIBMULTITHREAD="$LIBTHREAD"
-          LTLIBMULTITHREAD="$LTLIBTHREAD"
-          AC_DEFINE([USE_SOLARIS_THREADS], [1],
-            [Define if the old Solaris multithreading library can be used.])
-          if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
-            AC_DEFINE([USE_SOLARIS_THREADS_WEAK], [1],
-              [Define if references to the old Solaris multithreading library should be made weak.])
-            LIBTHREAD=
-            LTLIBTHREAD=
-          fi
-        fi
+    if test $gl_threads_api = none; then
+      if test "$gl_use_threads" = isoc && test "$gl_have_isoc_threads" = yes; then
+        gl_STDTHREADLIB_BODY
+        LIBTHREAD=$LIBSTDTHREAD LTLIBTHREAD=$LIBSTDTHREAD
+        LIBMULTITHREAD=$LIBSTDTHREAD LTLIBMULTITHREAD=$LIBSTDTHREAD
+        gl_threads_api=isoc
+        AC_DEFINE([USE_ISOC_THREADS], [1],
+          [Define if the ISO C multithreading library can be used.])
       fi
     fi
-    if test "$gl_use_threads" = pth; then
-      gl_save_CPPFLAGS="$CPPFLAGS"
-      AC_LIB_LINKFLAGS([pth])
-      gl_have_pth=
-      gl_save_LIBS="$LIBS"
-      LIBS="$LIBS $LIBPTH"
-      AC_LINK_IFELSE(
-        [AC_LANG_PROGRAM([[#include <pth.h>]], [[pth_self();]])],
-        [gl_have_pth=yes])
-      LIBS="$gl_save_LIBS"
-      if test -n "$gl_have_pth"; then
-        gl_threads_api=pth
-        LIBTHREAD="$LIBPTH"
-        LTLIBTHREAD="$LTLIBPTH"
-        LIBMULTITHREAD="$LIBTHREAD"
-        LTLIBMULTITHREAD="$LTLIBTHREAD"
-        AC_DEFINE([USE_PTH_THREADS], [1],
-          [Define if the GNU Pth multithreading library can be used.])
-        if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
-          if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
-            AC_DEFINE([USE_PTH_THREADS_WEAK], [1],
-              [Define if references to the GNU Pth multithreading library should be made weak.])
-            LIBTHREAD=
-            LTLIBTHREAD=
-          fi
-        fi
-      else
-        CPPFLAGS="$gl_save_CPPFLAGS"
-      fi
-    fi
-    if test -z "$gl_have_pthread"; then
+    if test $gl_threads_api = none; then
       case "$gl_use_threads" in
         yes | windows | win32) # The 'win32' is for backward compatibility.
           if { case "$host_os" in
@@ -317,6 +596,21 @@ AC_DEFUN([gl_DISABLE_THREADS], [
 ])
 
 
+dnl gl_AVOID_WINPTHREAD
+dnl -------------------
+dnl Sets the gl_THREADLIB default so that on mingw, a dependency to the
+dnl libwinpthread DLL (mingw-w64 winpthreads library) is avoided.
+dnl The user can still override it at installation time, by using the
+dnl configure option '--enable-threads'.
+
+AC_DEFUN([gl_AVOID_WINPTHREAD], [
+  m4_divert_text([INIT_PREPARE], [gl_use_winpthreads_default=no])
+])
+
+
+dnl ============================================================================
+
+
 dnl Survey of platforms:
 dnl
 dnl Platform           Available  Compiler    Supports   test-lock
@@ -324,7 +618,11 @@ dnl                    flavours   option      weak       result
 dnl ---------------    ---------  ---------   --------   ---------
 dnl Linux 2.4/glibc    posix      -lpthread       Y      OK
 dnl
-dnl GNU Hurd/glibc     posix
+dnl Linux/glibc 2.34   posix                      Y      OK
+dnl
+dnl GNU Hurd/glibc     posix      -lpthread       Y      OK
+dnl
+dnl Ubuntu 14.04       posix      -pthread        Y      OK
 dnl
 dnl FreeBSD 5.3        posix      -lc_r           Y
 dnl                    posix      -lkse ?         Y
@@ -344,7 +642,6 @@ dnl
 dnl Mac OS X 10.[123]  posix      -lpthread       Y      OK
 dnl
 dnl Solaris 7,8,9      posix      -lpthread       Y      Sol 7,8: 0.0; Sol 9: OK
-dnl                    solaris    -lthread        Y      Sol 7,8: 0.0; Sol 9: OK
 dnl
 dnl HP-UX 11           posix      -lpthread       N (cc) OK
 dnl                                               Y (gcc)
@@ -358,8 +655,6 @@ dnl                               -lpthread (gcc) Y
 dnl
 dnl Cygwin             posix      -lpthread       Y      OK
 dnl
-dnl Any of the above   pth        -lpth                  0.0
-dnl
 dnl Mingw              windows                    N      OK
 dnl
 dnl BeOS 5             --
diff --git a/gl/m4/time_h.m4 b/gl/m4/time_h.m4
index 3b839005..f6bf3a4f 100644
--- a/gl/m4/time_h.m4
+++ b/gl/m4/time_h.m4
@@ -1,8 +1,8 @@
 # Configure a more-standard replacement for <time.h>.
 
-# Copyright (C) 2000-2001, 2003-2007, 2009-2013 Free Software Foundation, Inc.
+# Copyright (C) 2000-2001, 2003-2007, 2009-2023 Free Software Foundation, Inc.
 
-# serial 7
+# serial 20
 
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -10,23 +10,42 @@
 
 # Written by Paul Eggert and Jim Meyering.
 
-AC_DEFUN([gl_HEADER_TIME_H],
+AC_DEFUN_ONCE([gl_TIME_H],
 [
-  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
-  dnl once only, before all statements that occur in other macros.
-  AC_REQUIRE([gl_HEADER_TIME_H_BODY])
-])
+  dnl Ensure to expand the default settings once only, before all statements
+  dnl that occur in other macros.
+  AC_REQUIRE([gl_TIME_H_DEFAULTS])
 
-AC_DEFUN([gl_HEADER_TIME_H_BODY],
-[
-  AC_REQUIRE([AC_C_RESTRICT])
-  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
   gl_NEXT_HEADERS([time.h])
   AC_REQUIRE([gl_CHECK_TYPE_STRUCT_TIMESPEC])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+#include <time.h>
+    ]], [asctime_r ctime_r])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_CACHE_CHECK([for TIME_UTC in <time.h>],
+    [gl_cv_time_h_has_TIME_UTC],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <time.h>
+          ]],
+          [[static int x = TIME_UTC; x++;]])],
+       [gl_cv_time_h_has_TIME_UTC=yes],
+       [gl_cv_time_h_has_TIME_UTC=no])])
+  if test $gl_cv_time_h_has_TIME_UTC = yes; then
+    TIME_H_DEFINES_TIME_UTC=1
+  else
+    TIME_H_DEFINES_TIME_UTC=0
+  fi
+  AC_SUBST([TIME_H_DEFINES_TIME_UTC])
 ])
 
 dnl Check whether 'struct timespec' is declared
-dnl in time.h, sys/time.h, or pthread.h.
+dnl in time.h, sys/time.h, pthread.h, or unistd.h.
 
 AC_DEFUN([gl_CHECK_TYPE_STRUCT_TIMESPEC],
 [
@@ -44,6 +63,7 @@ AC_DEFUN([gl_CHECK_TYPE_STRUCT_TIMESPEC],
   TIME_H_DEFINES_STRUCT_TIMESPEC=0
   SYS_TIME_H_DEFINES_STRUCT_TIMESPEC=0
   PTHREAD_H_DEFINES_STRUCT_TIMESPEC=0
+  UNISTD_H_DEFINES_STRUCT_TIMESPEC=0
   if test $gl_cv_sys_struct_timespec_in_time_h = yes; then
     TIME_H_DEFINES_STRUCT_TIMESPEC=1
   else
@@ -70,40 +90,94 @@ AC_DEFUN([gl_CHECK_TYPE_STRUCT_TIMESPEC],
            [gl_cv_sys_struct_timespec_in_pthread_h=no])])
       if test $gl_cv_sys_struct_timespec_in_pthread_h = yes; then
         PTHREAD_H_DEFINES_STRUCT_TIMESPEC=1
+      else
+        AC_CACHE_CHECK([for struct timespec in <unistd.h>],
+          [gl_cv_sys_struct_timespec_in_unistd_h],
+          [AC_COMPILE_IFELSE(
+             [AC_LANG_PROGRAM(
+                [[#include <unistd.h>
+                ]],
+                [[static struct timespec x; x.tv_sec = x.tv_nsec;]])],
+             [gl_cv_sys_struct_timespec_in_unistd_h=yes],
+             [gl_cv_sys_struct_timespec_in_unistd_h=no])])
+        if test $gl_cv_sys_struct_timespec_in_unistd_h = yes; then
+          UNISTD_H_DEFINES_STRUCT_TIMESPEC=1
+        fi
       fi
     fi
   fi
   AC_SUBST([TIME_H_DEFINES_STRUCT_TIMESPEC])
   AC_SUBST([SYS_TIME_H_DEFINES_STRUCT_TIMESPEC])
   AC_SUBST([PTHREAD_H_DEFINES_STRUCT_TIMESPEC])
+  AC_SUBST([UNISTD_H_DEFINES_STRUCT_TIMESPEC])
 ])
 
+# gl_TIME_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_TIME_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_TIME_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
-AC_DEFUN([gl_HEADER_TIME_H_DEFAULTS],
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_TIME_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_TIME_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CTIME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MKTIME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LOCALTIME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_NANOSLEEP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRFTIME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRPTIME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TIMEGM])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TIMESPEC_GET])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TIMESPEC_GETRES])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TIME_R])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TIME_RZ])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TZSET])
+    dnl Support Microsoft deprecated alias function names by default.
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_TZSET], [1])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_TIME_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_TIME_H_DEFAULTS])
+])
+
+AC_DEFUN([gl_TIME_H_DEFAULTS],
 [
-  GNULIB_MKTIME=0;                       AC_SUBST([GNULIB_MKTIME])
-  GNULIB_NANOSLEEP=0;                    AC_SUBST([GNULIB_NANOSLEEP])
-  GNULIB_STRPTIME=0;                     AC_SUBST([GNULIB_STRPTIME])
-  GNULIB_TIMEGM=0;                       AC_SUBST([GNULIB_TIMEGM])
-  GNULIB_TIME_R=0;                       AC_SUBST([GNULIB_TIME_R])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_DECL_LOCALTIME_R=1;               AC_SUBST([HAVE_DECL_LOCALTIME_R])
   HAVE_NANOSLEEP=1;                      AC_SUBST([HAVE_NANOSLEEP])
   HAVE_STRPTIME=1;                       AC_SUBST([HAVE_STRPTIME])
   HAVE_TIMEGM=1;                         AC_SUBST([HAVE_TIMEGM])
+  HAVE_TIMESPEC_GET=1;                   AC_SUBST([HAVE_TIMESPEC_GET])
+  HAVE_TIMESPEC_GETRES=1;                AC_SUBST([HAVE_TIMESPEC_GETRES])
+  dnl Even GNU libc does not have timezone_t yet.
+  HAVE_TIMEZONE_T=0;                     AC_SUBST([HAVE_TIMEZONE_T])
   dnl If another module says to replace or to not replace, do that.
   dnl Otherwise, replace only if someone compiles with -DGNULIB_PORTCHECK;
   dnl this lets maintainers check for portability.
+  REPLACE_CTIME=GNULIB_PORTCHECK;        AC_SUBST([REPLACE_CTIME])
   REPLACE_LOCALTIME_R=GNULIB_PORTCHECK;  AC_SUBST([REPLACE_LOCALTIME_R])
   REPLACE_MKTIME=GNULIB_PORTCHECK;       AC_SUBST([REPLACE_MKTIME])
   REPLACE_NANOSLEEP=GNULIB_PORTCHECK;    AC_SUBST([REPLACE_NANOSLEEP])
+  REPLACE_STRFTIME=GNULIB_PORTCHECK;     AC_SUBST([REPLACE_STRFTIME])
   REPLACE_TIMEGM=GNULIB_PORTCHECK;       AC_SUBST([REPLACE_TIMEGM])
+  REPLACE_TZSET=GNULIB_PORTCHECK;        AC_SUBST([REPLACE_TZSET])
+
+  dnl Hack so that the time module doesn't depend on the sys_time module.
+  dnl First, default GNULIB_GETTIMEOFDAY to 0 if sys_time is absent.
+  : ${GNULIB_GETTIMEOFDAY=0};            AC_SUBST([GNULIB_GETTIMEOFDAY])
+  dnl Second, it's OK to not use GNULIB_PORTCHECK for REPLACE_GMTIME
+  dnl and REPLACE_LOCALTIME, as portability to Solaris 2.6 and earlier
+  dnl is no longer a big deal.
+  REPLACE_GMTIME=0;                      AC_SUBST([REPLACE_GMTIME])
+  REPLACE_LOCALTIME=0;                   AC_SUBST([REPLACE_LOCALTIME])
 ])
diff --git a/gl/m4/time_r.m4 b/gl/m4/time_r.m4
index c388a831..adce438a 100644
--- a/gl/m4/time_r.m4
+++ b/gl/m4/time_r.m4
@@ -1,6 +1,6 @@
 dnl Reentrant time functions: localtime_r, gmtime_r.
 
-dnl Copyright (C) 2003, 2006-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2003, 2006-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -12,12 +12,20 @@ AC_DEFUN([gl_TIME_R],
   dnl Persuade glibc and Solaris <time.h> to declare localtime_r.
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
 
-  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
+  AC_REQUIRE([gl_TIME_H_DEFAULTS])
   AC_REQUIRE([AC_C_RESTRICT])
 
   dnl Some systems don't declare localtime_r() and gmtime_r() if _REENTRANT is
   dnl not defined.
-  AC_CHECK_DECLS([localtime_r], [], [], [[#include <time.h>]])
+  AC_CHECK_DECLS([localtime_r], [], [],
+    [[/* mingw's <time.h> provides the functions asctime_r, ctime_r,
+         gmtime_r, localtime_r only if <unistd.h> or <pthread.h> has
+         been included before.  */
+      #if defined __MINGW32__
+      # include <unistd.h>
+      #endif
+      #include <time.h>
+    ]])
   if test $ac_cv_have_decl_localtime_r = no; then
     HAVE_DECL_LOCALTIME_R=0
   fi
@@ -29,7 +37,14 @@ AC_DEFUN([gl_TIME_R],
       [gl_cv_time_r_posix],
       [AC_COMPILE_IFELSE(
          [AC_LANG_PROGRAM(
-            [[#include <time.h>]],
+            [[/* mingw's <time.h> provides the functions asctime_r, ctime_r,
+                 gmtime_r, localtime_r only if <unistd.h> or <pthread.h> has
+                 been included before.  */
+              #if defined __MINGW32__
+              # include <unistd.h>
+              #endif
+              #include <time.h>
+            ]],
             [[/* We don't need to append 'restrict's to the argument types,
                  even though the POSIX signature has the 'restrict's,
                  since C99 says they can't affect type compatibility.  */
@@ -49,6 +64,32 @@ AC_DEFUN([gl_TIME_R],
     fi
   else
     HAVE_LOCALTIME_R=0
+    dnl On mingw, localtime_r() is defined as an inline function; use through a
+    dnl direct function call works but the use as a function pointer leads to a
+    dnl link error.
+    AC_CACHE_CHECK([whether localtime_r exists as an inline function],
+      [gl_cv_func_localtime_r_inline],
+      [AC_LINK_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[/* mingw's <time.h> provides the functions asctime_r, ctime_r,
+                 gmtime_r, localtime_r only if <unistd.h> or <pthread.h> has
+                 been included before.  */
+              #if defined __MINGW32__
+              # include <unistd.h>
+              #endif
+              #include <time.h>
+            ]],
+            [[time_t a;
+              struct tm r;
+              localtime_r (&a, &r);
+            ]])
+         ],
+         [gl_cv_func_localtime_r_inline=yes],
+         [gl_cv_func_localtime_r_inline=no])
+      ])
+    if test $gl_cv_func_localtime_r_inline = yes; then
+      REPLACE_LOCALTIME_R=1
+    fi
   fi
 ])
 
diff --git a/gl/m4/timegm.m4 b/gl/m4/timegm.m4
index 997953c0..6079f1a3 100644
--- a/gl/m4/timegm.m4
+++ b/gl/m4/timegm.m4
@@ -1,17 +1,17 @@
-# timegm.m4 serial 11
-dnl Copyright (C) 2003, 2007, 2009-2013 Free Software Foundation, Inc.
+# timegm.m4 serial 13
+dnl Copyright (C) 2003, 2007, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_TIMEGM],
 [
-  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
-  AC_REQUIRE([gl_FUNC_MKTIME])
+  AC_REQUIRE([gl_TIME_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_MKTIME_WORKS])
   REPLACE_TIMEGM=0
   AC_CHECK_FUNCS_ONCE([timegm])
   if test $ac_cv_func_timegm = yes; then
-    if test $gl_cv_func_working_mktime = no; then
+    if test "$gl_cv_func_working_mktime" != yes; then
       # Assume that timegm is buggy if mktime is.
       REPLACE_TIMEGM=1
     fi
diff --git a/gl/m4/uintmax_t.m4 b/gl/m4/uintmax_t.m4
deleted file mode 100644
index c6ff8006..00000000
--- a/gl/m4/uintmax_t.m4
+++ /dev/null
@@ -1,30 +0,0 @@
-# uintmax_t.m4 serial 12
-dnl Copyright (C) 1997-2004, 2007-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-dnl From Paul Eggert.
-
-AC_PREREQ([2.13])
-
-# Define uintmax_t to 'unsigned long' or 'unsigned long long'
-# if it is not already defined in <stdint.h> or <inttypes.h>.
-
-AC_DEFUN([gl_AC_TYPE_UINTMAX_T],
-[
-  AC_REQUIRE([gl_AC_HEADER_INTTYPES_H])
-  AC_REQUIRE([gl_AC_HEADER_STDINT_H])
-  if test $gl_cv_header_inttypes_h = no && test $gl_cv_header_stdint_h = no; then
-    AC_REQUIRE([AC_TYPE_UNSIGNED_LONG_LONG_INT])
-    test $ac_cv_type_unsigned_long_long_int = yes \
-      && ac_type='unsigned long long' \
-      || ac_type='unsigned long'
-    AC_DEFINE_UNQUOTED([uintmax_t], [$ac_type],
-      [Define to unsigned long or unsigned long long
-       if <stdint.h> and <inttypes.h> don't define.])
-  else
-    AC_DEFINE([HAVE_UINTMAX_T], [1],
-      [Define if you have the 'uintmax_t' type in <stdint.h> or <inttypes.h>.])
-  fi
-])
diff --git a/gl/m4/ungetc.m4 b/gl/m4/ungetc.m4
new file mode 100644
index 00000000..8977a346
--- /dev/null
+++ b/gl/m4/ungetc.m4
@@ -0,0 +1,73 @@
+# ungetc.m4 serial 10
+dnl Copyright (C) 2009-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN_ONCE([gl_FUNC_UNGETC_WORKS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+  AC_CACHE_CHECK([whether ungetc works on arbitrary bytes],
+    [gl_cv_func_ungetc_works],
+    [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <stdio.h>
+      ]], [[FILE *f;
+            if (!(f = fopen ("conftest.tmp", "w+")))
+              return 1;
+            if (fputs ("abc", f) < 0)
+              { fclose (f); return 2; }
+            rewind (f);
+            if (fgetc (f) != 'a')
+              { fclose (f); return 3; }
+            if (fgetc (f) != 'b')
+              { fclose (f); return 4; }
+            if (ungetc ('d', f) != 'd')
+              { fclose (f); return 5; }
+            if (ftell (f) != 1)
+              { fclose (f); return 6; }
+            if (fgetc (f) != 'd')
+              { fclose (f); return 7; }
+            if (ftell (f) != 2)
+              { fclose (f); return 8; }
+            if (fseek (f, 0, SEEK_CUR) != 0)
+              { fclose (f); return 9; }
+            if (ftell (f) != 2)
+              { fclose (f); return 10; }
+            if (fgetc (f) != 'c')
+              { fclose (f); return 11; }
+            fclose (f);
+            remove ("conftest.tmp");
+          ]])],
+        [gl_cv_func_ungetc_works=yes], [gl_cv_func_ungetc_works=no],
+        [case "$host_os" in
+                          # Guess yes on glibc systems.
+           *-gnu* | gnu*) gl_cv_func_ungetc_works="guessing yes" ;;
+                          # Guess yes on musl systems.
+           *-musl*)       gl_cv_func_ungetc_works="guessing yes" ;;
+                          # Guess yes on bionic systems.
+           *-android*)    gl_cv_func_ungetc_works="guessing yes" ;;
+                          # Guess yes on native Windows.
+           mingw*)        gl_cv_func_ungetc_works="guessing yes" ;;
+                          # If we don't know, obey --enable-cross-guesses.
+           *)             gl_cv_func_ungetc_works="$gl_cross_guess_normal" ;;
+         esac
+        ])
+    ])
+  gl_ftello_broken_after_ungetc=no
+  case "$gl_cv_func_ungetc_works" in
+    *yes) ;;
+    *)
+      dnl On macOS >= 10.15, where the above program fails with exit code 6,
+      dnl we fix it through an ftello override.
+      case "$host_os" in
+        darwin*) gl_ftello_broken_after_ungetc=yes ;;
+        *)
+          AC_DEFINE([FUNC_UNGETC_BROKEN], [1],
+            [Define to 1 if ungetc is broken when used on arbitrary bytes.])
+          ;;
+      esac
+      ;;
+  esac
+])
diff --git a/gl/m4/unistd_h.m4 b/gl/m4/unistd_h.m4
index 32dcfa58..f4384027 100644
--- a/gl/m4/unistd_h.m4
+++ b/gl/m4/unistd_h.m4
@@ -1,15 +1,15 @@
-# unistd_h.m4 serial 66
-dnl Copyright (C) 2006-2013 Free Software Foundation, Inc.
+# unistd_h.m4 serial 90
+dnl Copyright (C) 2006-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl Written by Simon Josefsson, Bruno Haible.
 
-AC_DEFUN([gl_UNISTD_H],
+AC_DEFUN_ONCE([gl_UNISTD_H],
 [
-  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
-  dnl once only, before all statements that occur in other macros.
+  dnl Ensure to expand the default settings once only, before all statements
+  dnl that occur in other macros.
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
 
   gl_CHECK_NEXT_HEADERS([unistd.h])
@@ -37,150 +37,234 @@ AC_DEFUN([gl_UNISTD_H],
 # include <fcntl.h>
 # include <stdio.h>
 # include <stdlib.h>
-# if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+# if defined _WIN32 && ! defined __CYGWIN__
 #  include <io.h>
 # endif
 #endif
-    ]], [chdir chown dup dup2 dup3 environ euidaccess faccessat fchdir fchownat
-    fdatasync fsync ftruncate getcwd getdomainname getdtablesize getgroups
-    gethostname getlogin getlogin_r getpagesize
+    ]], [access chdir chown copy_file_range dup dup2 dup3 environ euidaccess
+    execl execle execlp execv execve execvp execvpe
+    faccessat fchdir
+    fchownat fdatasync fsync ftruncate getcwd getdomainname getdtablesize
+    getentropy getgroups gethostname getlogin getlogin_r getpagesize getpass
     getusershell setusershell endusershell
     group_member isatty lchown link linkat lseek pipe pipe2 pread pwrite
-    readlink readlinkat rmdir sethostname sleep symlink symlinkat ttyname_r
-    unlink unlinkat usleep])
+    readlink readlinkat rmdir sethostname sleep symlink symlinkat
+    truncate ttyname_r unlink unlinkat usleep])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_CHECK_DECLS_ONCE([execvpe])
+  if test $ac_cv_have_decl_execvpe = no; then
+    HAVE_DECL_EXECVPE=0
+  fi
 ])
 
+# gl_UNISTD_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_UNISTD_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_UNISTD_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_UNISTD_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_UNISTD_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ACCESS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CHDIR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CHOWN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CLOSE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_COPY_FILE_RANGE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_DUP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_DUP2])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_DUP3])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ENVIRON])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EUIDACCESS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXECL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXECLE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXECLP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXECV])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXECVE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXECVP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_EXECVPE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FACCESSAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FCHDIR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FCHOWNAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FDATASYNC])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FSYNC])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FTRUNCATE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETCWD])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETDOMAINNAME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETDTABLESIZE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETENTROPY])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETGROUPS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETHOSTNAME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETLOGIN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETLOGIN_R])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETOPT_POSIX])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETPAGESIZE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETPASS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETPASS_GNU])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETUSERSHELL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GROUP_MEMBER])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISATTY])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LCHOWN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LINK])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LINKAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_LSEEK])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PIPE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PIPE2])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PREAD])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PWRITE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_READ])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_READLINK])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_READLINKAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_RMDIR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SETHOSTNAME])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SLEEP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SYMLINK])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SYMLINKAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TRUNCATE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TTYNAME_R])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_UNISTD_H_GETOPT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_UNISTD_H_NONBLOCKING])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_UNISTD_H_SIGPIPE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_UNLINK])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_UNLINKAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_USLEEP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WRITE])
+    dnl Support Microsoft deprecated alias function names by default.
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_ACCESS], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_CHDIR], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_CLOSE], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_DUP], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_DUP2], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_EXECL], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_EXECLE], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_EXECLP], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_EXECV], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_EXECVE], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_EXECVP], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_EXECVPE], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_GETCWD], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_GETPID], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_ISATTY], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_LSEEK], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_READ], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_RMDIR], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_SWAB], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_UNLINK], [1])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_WRITE], [1])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_UNISTD_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_UNISTD_H_DEFAULTS],
 [
-  GNULIB_CHDIR=0;                AC_SUBST([GNULIB_CHDIR])
-  GNULIB_CHOWN=0;                AC_SUBST([GNULIB_CHOWN])
-  GNULIB_CLOSE=0;                AC_SUBST([GNULIB_CLOSE])
-  GNULIB_DUP=0;                  AC_SUBST([GNULIB_DUP])
-  GNULIB_DUP2=0;                 AC_SUBST([GNULIB_DUP2])
-  GNULIB_DUP3=0;                 AC_SUBST([GNULIB_DUP3])
-  GNULIB_ENVIRON=0;              AC_SUBST([GNULIB_ENVIRON])
-  GNULIB_EUIDACCESS=0;           AC_SUBST([GNULIB_EUIDACCESS])
-  GNULIB_FACCESSAT=0;            AC_SUBST([GNULIB_FACCESSAT])
-  GNULIB_FCHDIR=0;               AC_SUBST([GNULIB_FCHDIR])
-  GNULIB_FCHOWNAT=0;             AC_SUBST([GNULIB_FCHOWNAT])
-  GNULIB_FDATASYNC=0;            AC_SUBST([GNULIB_FDATASYNC])
-  GNULIB_FSYNC=0;                AC_SUBST([GNULIB_FSYNC])
-  GNULIB_FTRUNCATE=0;            AC_SUBST([GNULIB_FTRUNCATE])
-  GNULIB_GETCWD=0;               AC_SUBST([GNULIB_GETCWD])
-  GNULIB_GETDOMAINNAME=0;        AC_SUBST([GNULIB_GETDOMAINNAME])
-  GNULIB_GETDTABLESIZE=0;        AC_SUBST([GNULIB_GETDTABLESIZE])
-  GNULIB_GETGROUPS=0;            AC_SUBST([GNULIB_GETGROUPS])
-  GNULIB_GETHOSTNAME=0;          AC_SUBST([GNULIB_GETHOSTNAME])
-  GNULIB_GETLOGIN=0;             AC_SUBST([GNULIB_GETLOGIN])
-  GNULIB_GETLOGIN_R=0;           AC_SUBST([GNULIB_GETLOGIN_R])
-  GNULIB_GETPAGESIZE=0;          AC_SUBST([GNULIB_GETPAGESIZE])
-  GNULIB_GETUSERSHELL=0;         AC_SUBST([GNULIB_GETUSERSHELL])
-  GNULIB_GROUP_MEMBER=0;         AC_SUBST([GNULIB_GROUP_MEMBER])
-  GNULIB_ISATTY=0;               AC_SUBST([GNULIB_ISATTY])
-  GNULIB_LCHOWN=0;               AC_SUBST([GNULIB_LCHOWN])
-  GNULIB_LINK=0;                 AC_SUBST([GNULIB_LINK])
-  GNULIB_LINKAT=0;               AC_SUBST([GNULIB_LINKAT])
-  GNULIB_LSEEK=0;                AC_SUBST([GNULIB_LSEEK])
-  GNULIB_PIPE=0;                 AC_SUBST([GNULIB_PIPE])
-  GNULIB_PIPE2=0;                AC_SUBST([GNULIB_PIPE2])
-  GNULIB_PREAD=0;                AC_SUBST([GNULIB_PREAD])
-  GNULIB_PWRITE=0;               AC_SUBST([GNULIB_PWRITE])
-  GNULIB_READ=0;                 AC_SUBST([GNULIB_READ])
-  GNULIB_READLINK=0;             AC_SUBST([GNULIB_READLINK])
-  GNULIB_READLINKAT=0;           AC_SUBST([GNULIB_READLINKAT])
-  GNULIB_RMDIR=0;                AC_SUBST([GNULIB_RMDIR])
-  GNULIB_SETHOSTNAME=0;          AC_SUBST([GNULIB_SETHOSTNAME])
-  GNULIB_SLEEP=0;                AC_SUBST([GNULIB_SLEEP])
-  GNULIB_SYMLINK=0;              AC_SUBST([GNULIB_SYMLINK])
-  GNULIB_SYMLINKAT=0;            AC_SUBST([GNULIB_SYMLINKAT])
-  GNULIB_TTYNAME_R=0;            AC_SUBST([GNULIB_TTYNAME_R])
-  GNULIB_UNISTD_H_NONBLOCKING=0; AC_SUBST([GNULIB_UNISTD_H_NONBLOCKING])
-  GNULIB_UNISTD_H_SIGPIPE=0;     AC_SUBST([GNULIB_UNISTD_H_SIGPIPE])
-  GNULIB_UNLINK=0;               AC_SUBST([GNULIB_UNLINK])
-  GNULIB_UNLINKAT=0;             AC_SUBST([GNULIB_UNLINKAT])
-  GNULIB_USLEEP=0;               AC_SUBST([GNULIB_USLEEP])
-  GNULIB_WRITE=0;                AC_SUBST([GNULIB_WRITE])
   dnl Assume proper GNU behavior unless another module says otherwise.
-  HAVE_CHOWN=1;           AC_SUBST([HAVE_CHOWN])
-  HAVE_DUP2=1;            AC_SUBST([HAVE_DUP2])
-  HAVE_DUP3=1;            AC_SUBST([HAVE_DUP3])
-  HAVE_EUIDACCESS=1;      AC_SUBST([HAVE_EUIDACCESS])
-  HAVE_FACCESSAT=1;       AC_SUBST([HAVE_FACCESSAT])
-  HAVE_FCHDIR=1;          AC_SUBST([HAVE_FCHDIR])
-  HAVE_FCHOWNAT=1;        AC_SUBST([HAVE_FCHOWNAT])
-  HAVE_FDATASYNC=1;       AC_SUBST([HAVE_FDATASYNC])
-  HAVE_FSYNC=1;           AC_SUBST([HAVE_FSYNC])
-  HAVE_FTRUNCATE=1;       AC_SUBST([HAVE_FTRUNCATE])
-  HAVE_GETDTABLESIZE=1;   AC_SUBST([HAVE_GETDTABLESIZE])
-  HAVE_GETGROUPS=1;       AC_SUBST([HAVE_GETGROUPS])
-  HAVE_GETHOSTNAME=1;     AC_SUBST([HAVE_GETHOSTNAME])
-  HAVE_GETLOGIN=1;        AC_SUBST([HAVE_GETLOGIN])
-  HAVE_GETPAGESIZE=1;     AC_SUBST([HAVE_GETPAGESIZE])
-  HAVE_GROUP_MEMBER=1;    AC_SUBST([HAVE_GROUP_MEMBER])
-  HAVE_LCHOWN=1;          AC_SUBST([HAVE_LCHOWN])
-  HAVE_LINK=1;            AC_SUBST([HAVE_LINK])
-  HAVE_LINKAT=1;          AC_SUBST([HAVE_LINKAT])
-  HAVE_PIPE=1;            AC_SUBST([HAVE_PIPE])
-  HAVE_PIPE2=1;           AC_SUBST([HAVE_PIPE2])
-  HAVE_PREAD=1;           AC_SUBST([HAVE_PREAD])
-  HAVE_PWRITE=1;          AC_SUBST([HAVE_PWRITE])
-  HAVE_READLINK=1;        AC_SUBST([HAVE_READLINK])
-  HAVE_READLINKAT=1;      AC_SUBST([HAVE_READLINKAT])
-  HAVE_SETHOSTNAME=1;     AC_SUBST([HAVE_SETHOSTNAME])
-  HAVE_SLEEP=1;           AC_SUBST([HAVE_SLEEP])
-  HAVE_SYMLINK=1;         AC_SUBST([HAVE_SYMLINK])
-  HAVE_SYMLINKAT=1;       AC_SUBST([HAVE_SYMLINKAT])
-  HAVE_UNLINKAT=1;        AC_SUBST([HAVE_UNLINKAT])
-  HAVE_USLEEP=1;          AC_SUBST([HAVE_USLEEP])
-  HAVE_DECL_ENVIRON=1;    AC_SUBST([HAVE_DECL_ENVIRON])
-  HAVE_DECL_FCHDIR=1;     AC_SUBST([HAVE_DECL_FCHDIR])
-  HAVE_DECL_FDATASYNC=1;  AC_SUBST([HAVE_DECL_FDATASYNC])
-  HAVE_DECL_GETDOMAINNAME=1; AC_SUBST([HAVE_DECL_GETDOMAINNAME])
-  HAVE_DECL_GETLOGIN_R=1; AC_SUBST([HAVE_DECL_GETLOGIN_R])
-  HAVE_DECL_GETPAGESIZE=1; AC_SUBST([HAVE_DECL_GETPAGESIZE])
-  HAVE_DECL_GETUSERSHELL=1; AC_SUBST([HAVE_DECL_GETUSERSHELL])
-  HAVE_DECL_SETHOSTNAME=1; AC_SUBST([HAVE_DECL_SETHOSTNAME])
-  HAVE_DECL_TTYNAME_R=1;  AC_SUBST([HAVE_DECL_TTYNAME_R])
-  HAVE_OS_H=0;            AC_SUBST([HAVE_OS_H])
-  HAVE_SYS_PARAM_H=0;     AC_SUBST([HAVE_SYS_PARAM_H])
-  REPLACE_CHOWN=0;        AC_SUBST([REPLACE_CHOWN])
-  REPLACE_CLOSE=0;        AC_SUBST([REPLACE_CLOSE])
-  REPLACE_DUP=0;          AC_SUBST([REPLACE_DUP])
-  REPLACE_DUP2=0;         AC_SUBST([REPLACE_DUP2])
-  REPLACE_FCHOWNAT=0;     AC_SUBST([REPLACE_FCHOWNAT])
-  REPLACE_FTRUNCATE=0;    AC_SUBST([REPLACE_FTRUNCATE])
-  REPLACE_GETCWD=0;       AC_SUBST([REPLACE_GETCWD])
-  REPLACE_GETDOMAINNAME=0; AC_SUBST([REPLACE_GETDOMAINNAME])
-  REPLACE_GETLOGIN_R=0;   AC_SUBST([REPLACE_GETLOGIN_R])
-  REPLACE_GETGROUPS=0;    AC_SUBST([REPLACE_GETGROUPS])
-  REPLACE_GETPAGESIZE=0;  AC_SUBST([REPLACE_GETPAGESIZE])
-  REPLACE_ISATTY=0;       AC_SUBST([REPLACE_ISATTY])
-  REPLACE_LCHOWN=0;       AC_SUBST([REPLACE_LCHOWN])
-  REPLACE_LINK=0;         AC_SUBST([REPLACE_LINK])
-  REPLACE_LINKAT=0;       AC_SUBST([REPLACE_LINKAT])
-  REPLACE_LSEEK=0;        AC_SUBST([REPLACE_LSEEK])
-  REPLACE_PREAD=0;        AC_SUBST([REPLACE_PREAD])
-  REPLACE_PWRITE=0;       AC_SUBST([REPLACE_PWRITE])
-  REPLACE_READ=0;         AC_SUBST([REPLACE_READ])
-  REPLACE_READLINK=0;     AC_SUBST([REPLACE_READLINK])
-  REPLACE_RMDIR=0;        AC_SUBST([REPLACE_RMDIR])
-  REPLACE_SLEEP=0;        AC_SUBST([REPLACE_SLEEP])
-  REPLACE_SYMLINK=0;      AC_SUBST([REPLACE_SYMLINK])
-  REPLACE_TTYNAME_R=0;    AC_SUBST([REPLACE_TTYNAME_R])
-  REPLACE_UNLINK=0;       AC_SUBST([REPLACE_UNLINK])
-  REPLACE_UNLINKAT=0;     AC_SUBST([REPLACE_UNLINKAT])
-  REPLACE_USLEEP=0;       AC_SUBST([REPLACE_USLEEP])
-  REPLACE_WRITE=0;        AC_SUBST([REPLACE_WRITE])
-  UNISTD_H_HAVE_WINSOCK2_H=0; AC_SUBST([UNISTD_H_HAVE_WINSOCK2_H])
+  HAVE_CHOWN=1;                      AC_SUBST([HAVE_CHOWN])
+  HAVE_COPY_FILE_RANGE=1;            AC_SUBST([HAVE_COPY_FILE_RANGE])
+  HAVE_DUP3=1;                       AC_SUBST([HAVE_DUP3])
+  HAVE_EUIDACCESS=1;                 AC_SUBST([HAVE_EUIDACCESS])
+  HAVE_EXECVPE=1;                    AC_SUBST([HAVE_EXECVPE])
+  HAVE_FACCESSAT=1;                  AC_SUBST([HAVE_FACCESSAT])
+  HAVE_FCHDIR=1;                     AC_SUBST([HAVE_FCHDIR])
+  HAVE_FCHOWNAT=1;                   AC_SUBST([HAVE_FCHOWNAT])
+  HAVE_FDATASYNC=1;                  AC_SUBST([HAVE_FDATASYNC])
+  HAVE_FSYNC=1;                      AC_SUBST([HAVE_FSYNC])
+  HAVE_FTRUNCATE=1;                  AC_SUBST([HAVE_FTRUNCATE])
+  HAVE_GETDTABLESIZE=1;              AC_SUBST([HAVE_GETDTABLESIZE])
+  HAVE_GETENTROPY=1;                 AC_SUBST([HAVE_GETENTROPY])
+  HAVE_GETGROUPS=1;                  AC_SUBST([HAVE_GETGROUPS])
+  HAVE_GETHOSTNAME=1;                AC_SUBST([HAVE_GETHOSTNAME])
+  HAVE_GETLOGIN=1;                   AC_SUBST([HAVE_GETLOGIN])
+  HAVE_GETPAGESIZE=1;                AC_SUBST([HAVE_GETPAGESIZE])
+  HAVE_GETPASS=1;                    AC_SUBST([HAVE_GETPASS])
+  HAVE_GROUP_MEMBER=1;               AC_SUBST([HAVE_GROUP_MEMBER])
+  HAVE_LCHOWN=1;                     AC_SUBST([HAVE_LCHOWN])
+  HAVE_LINK=1;                       AC_SUBST([HAVE_LINK])
+  HAVE_LINKAT=1;                     AC_SUBST([HAVE_LINKAT])
+  HAVE_PIPE=1;                       AC_SUBST([HAVE_PIPE])
+  HAVE_PIPE2=1;                      AC_SUBST([HAVE_PIPE2])
+  HAVE_PREAD=1;                      AC_SUBST([HAVE_PREAD])
+  HAVE_PWRITE=1;                     AC_SUBST([HAVE_PWRITE])
+  HAVE_READLINK=1;                   AC_SUBST([HAVE_READLINK])
+  HAVE_READLINKAT=1;                 AC_SUBST([HAVE_READLINKAT])
+  HAVE_SETHOSTNAME=1;                AC_SUBST([HAVE_SETHOSTNAME])
+  HAVE_SLEEP=1;                      AC_SUBST([HAVE_SLEEP])
+  HAVE_SYMLINK=1;                    AC_SUBST([HAVE_SYMLINK])
+  HAVE_SYMLINKAT=1;                  AC_SUBST([HAVE_SYMLINKAT])
+  HAVE_UNLINKAT=1;                   AC_SUBST([HAVE_UNLINKAT])
+  HAVE_USLEEP=1;                     AC_SUBST([HAVE_USLEEP])
+  HAVE_DECL_ENVIRON=1;               AC_SUBST([HAVE_DECL_ENVIRON])
+  HAVE_DECL_EXECVPE=1;               AC_SUBST([HAVE_DECL_EXECVPE])
+  HAVE_DECL_FCHDIR=1;                AC_SUBST([HAVE_DECL_FCHDIR])
+  HAVE_DECL_FDATASYNC=1;             AC_SUBST([HAVE_DECL_FDATASYNC])
+  HAVE_DECL_GETDOMAINNAME=1;         AC_SUBST([HAVE_DECL_GETDOMAINNAME])
+  HAVE_DECL_GETLOGIN=1;              AC_SUBST([HAVE_DECL_GETLOGIN])
+  HAVE_DECL_GETLOGIN_R=1;            AC_SUBST([HAVE_DECL_GETLOGIN_R])
+  HAVE_DECL_GETPAGESIZE=1;           AC_SUBST([HAVE_DECL_GETPAGESIZE])
+  HAVE_DECL_GETUSERSHELL=1;          AC_SUBST([HAVE_DECL_GETUSERSHELL])
+  HAVE_DECL_SETHOSTNAME=1;           AC_SUBST([HAVE_DECL_SETHOSTNAME])
+  HAVE_DECL_TRUNCATE=1;              AC_SUBST([HAVE_DECL_TRUNCATE])
+  HAVE_DECL_TTYNAME_R=1;             AC_SUBST([HAVE_DECL_TTYNAME_R])
+  HAVE_OS_H=0;                       AC_SUBST([HAVE_OS_H])
+  HAVE_SYS_PARAM_H=0;                AC_SUBST([HAVE_SYS_PARAM_H])
+  REPLACE_ACCESS=0;                  AC_SUBST([REPLACE_ACCESS])
+  REPLACE_CHOWN=0;                   AC_SUBST([REPLACE_CHOWN])
+  REPLACE_CLOSE=0;                   AC_SUBST([REPLACE_CLOSE])
+  REPLACE_COPY_FILE_RANGE=0;         AC_SUBST([REPLACE_COPY_FILE_RANGE])
+  REPLACE_DUP=0;                     AC_SUBST([REPLACE_DUP])
+  REPLACE_DUP2=0;                    AC_SUBST([REPLACE_DUP2])
+  REPLACE_EXECL=0;                   AC_SUBST([REPLACE_EXECL])
+  REPLACE_EXECLE=0;                  AC_SUBST([REPLACE_EXECLE])
+  REPLACE_EXECLP=0;                  AC_SUBST([REPLACE_EXECLP])
+  REPLACE_EXECV=0;                   AC_SUBST([REPLACE_EXECV])
+  REPLACE_EXECVE=0;                  AC_SUBST([REPLACE_EXECVE])
+  REPLACE_EXECVP=0;                  AC_SUBST([REPLACE_EXECVP])
+  REPLACE_EXECVPE=0;                 AC_SUBST([REPLACE_EXECVPE])
+  REPLACE_FACCESSAT=0;               AC_SUBST([REPLACE_FACCESSAT])
+  REPLACE_FCHOWNAT=0;                AC_SUBST([REPLACE_FCHOWNAT])
+  REPLACE_FTRUNCATE=0;               AC_SUBST([REPLACE_FTRUNCATE])
+  REPLACE_GETCWD=0;                  AC_SUBST([REPLACE_GETCWD])
+  REPLACE_GETDOMAINNAME=0;           AC_SUBST([REPLACE_GETDOMAINNAME])
+  REPLACE_GETDTABLESIZE=0;           AC_SUBST([REPLACE_GETDTABLESIZE])
+  REPLACE_GETLOGIN_R=0;              AC_SUBST([REPLACE_GETLOGIN_R])
+  REPLACE_GETGROUPS=0;               AC_SUBST([REPLACE_GETGROUPS])
+  REPLACE_GETPAGESIZE=0;             AC_SUBST([REPLACE_GETPAGESIZE])
+  REPLACE_GETPASS=0;                 AC_SUBST([REPLACE_GETPASS])
+  REPLACE_GETPASS_FOR_GETPASS_GNU=0; AC_SUBST([REPLACE_GETPASS_FOR_GETPASS_GNU])
+  REPLACE_ISATTY=0;                  AC_SUBST([REPLACE_ISATTY])
+  REPLACE_LCHOWN=0;                  AC_SUBST([REPLACE_LCHOWN])
+  REPLACE_LINK=0;                    AC_SUBST([REPLACE_LINK])
+  REPLACE_LINKAT=0;                  AC_SUBST([REPLACE_LINKAT])
+  REPLACE_LSEEK=0;                   AC_SUBST([REPLACE_LSEEK])
+  REPLACE_PREAD=0;                   AC_SUBST([REPLACE_PREAD])
+  REPLACE_PWRITE=0;                  AC_SUBST([REPLACE_PWRITE])
+  REPLACE_READ=0;                    AC_SUBST([REPLACE_READ])
+  REPLACE_READLINK=0;                AC_SUBST([REPLACE_READLINK])
+  REPLACE_READLINKAT=0;              AC_SUBST([REPLACE_READLINKAT])
+  REPLACE_RMDIR=0;                   AC_SUBST([REPLACE_RMDIR])
+  REPLACE_SLEEP=0;                   AC_SUBST([REPLACE_SLEEP])
+  REPLACE_SYMLINK=0;                 AC_SUBST([REPLACE_SYMLINK])
+  REPLACE_SYMLINKAT=0;               AC_SUBST([REPLACE_SYMLINKAT])
+  REPLACE_TRUNCATE=0;                AC_SUBST([REPLACE_TRUNCATE])
+  REPLACE_TTYNAME_R=0;               AC_SUBST([REPLACE_TTYNAME_R])
+  REPLACE_UNLINK=0;                  AC_SUBST([REPLACE_UNLINK])
+  REPLACE_UNLINKAT=0;                AC_SUBST([REPLACE_UNLINKAT])
+  REPLACE_USLEEP=0;                  AC_SUBST([REPLACE_USLEEP])
+  REPLACE_WRITE=0;                   AC_SUBST([REPLACE_WRITE])
+  UNISTD_H_HAVE_SYS_RANDOM_H=0;      AC_SUBST([UNISTD_H_HAVE_SYS_RANDOM_H])
+  UNISTD_H_HAVE_WINSOCK2_H=0;        AC_SUBST([UNISTD_H_HAVE_WINSOCK2_H])
   UNISTD_H_HAVE_WINSOCK2_H_AND_USE_SOCKETS=0;
                            AC_SUBST([UNISTD_H_HAVE_WINSOCK2_H_AND_USE_SOCKETS])
 ])
diff --git a/gl/m4/unlocked-io.m4 b/gl/m4/unlocked-io.m4
new file mode 100644
index 00000000..407c0bac
--- /dev/null
+++ b/gl/m4/unlocked-io.m4
@@ -0,0 +1,36 @@
+# unlocked-io.m4 serial 16
+
+# Copyright (C) 1998-2006, 2009-2023 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl From Jim Meyering.
+dnl
+dnl See if the glibc *_unlocked I/O macros or functions are available.
+dnl Use only those *_unlocked macros or functions that are declared
+dnl (because some of them were declared in Solaris 2.5.1 but were removed
+dnl in Solaris 2.6, whereas we want binaries built on Solaris 2.5.1 to run
+dnl on Solaris 2.6).
+
+AC_DEFUN([gl_FUNC_GLIBC_UNLOCKED_IO],
+[
+  dnl Persuade glibc and Solaris <stdio.h> to declare
+  dnl fgets_unlocked(), fputs_unlocked() etc.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_DECLS_ONCE([clearerr_unlocked])
+  AC_CHECK_DECLS_ONCE([feof_unlocked])
+  AC_CHECK_DECLS_ONCE([ferror_unlocked])
+  AC_CHECK_DECLS_ONCE([fflush_unlocked])
+  AC_CHECK_DECLS_ONCE([fgets_unlocked])
+  AC_CHECK_DECLS_ONCE([fputc_unlocked])
+  AC_CHECK_DECLS_ONCE([fputs_unlocked])
+  AC_CHECK_DECLS_ONCE([fread_unlocked])
+  AC_CHECK_DECLS_ONCE([fwrite_unlocked])
+  AC_CHECK_DECLS_ONCE([getc_unlocked])
+  AC_CHECK_DECLS_ONCE([getchar_unlocked])
+  AC_CHECK_DECLS_ONCE([putc_unlocked])
+  AC_CHECK_DECLS_ONCE([putchar_unlocked])
+])
diff --git a/gl/m4/vararrays.m4 b/gl/m4/vararrays.m4
new file mode 100644
index 00000000..fd6230c2
--- /dev/null
+++ b/gl/m4/vararrays.m4
@@ -0,0 +1,72 @@
+# Check for variable-length arrays.
+
+# serial 6
+
+# From Paul Eggert
+
+# Copyright (C) 2001, 2009-2023 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+m4_version_prereq([2.70], [], [
+
+# AC_C_VARARRAYS
+# --------------
+# Check whether the C compiler supports variable-length arrays.
+AC_DEFUN([AC_C_VARARRAYS],
+[
+  AC_CACHE_CHECK([for variable-length arrays],
+    ac_cv_c_vararrays,
+    [AC_EGREP_CPP([defined],
+       [#ifdef __STDC_NO_VLA__
+        defined
+        #endif
+       ],
+       [ac_cv_c_vararrays='no: __STDC_NO_VLA__ is defined'],
+       [AC_COMPILE_IFELSE(
+          [AC_LANG_PROGRAM(
+             [[/* Test for VLA support.  This test is partly inspired
+                  from examples in the C standard.  Use at least two VLA
+                  functions to detect the GCC 3.4.3 bug described in:
+                  https://lists.gnu.org/archive/html/bug-gnulib/2014-08/msg00014.html
+                  */
+               #ifdef __STDC_NO_VLA__
+                syntax error;
+               #else
+                 extern int n;
+                 int B[100];
+                 int fvla (int m, int C[m][m]);
+
+                 int
+                 simple (int count, int all[static count])
+                 {
+                   return all[count - 1];
+                 }
+
+                 int
+                 fvla (int m, int C[m][m])
+                 {
+                   typedef int VLA[m][m];
+                   VLA x;
+                   int D[m];
+                   static int (*q)[m] = &B;
+                   int (*s)[n] = q;
+                   return C && &x[0][0] == &D[0] && &D[0] == s[0];
+                 }
+               #endif
+               ]])],
+          [ac_cv_c_vararrays=yes],
+          [ac_cv_c_vararrays=no])])])
+  if test "$ac_cv_c_vararrays" = yes; then
+    dnl This is for compatibility with Autoconf 2.61-2.69.
+    AC_DEFINE([HAVE_C_VARARRAYS], 1,
+      [Define to 1 if C supports variable-length arrays.])
+  elif test "$ac_cv_c_vararrays" = no; then
+    AC_DEFINE([__STDC_NO_VLA__], 1,
+      [Define to 1 if C does not support variable-length arrays, and
+       if the compiler does not already define this.])
+  fi
+])
+
+])
diff --git a/gl/m4/vasnprintf.m4 b/gl/m4/vasnprintf.m4
index d730e435..6361c843 100644
--- a/gl/m4/vasnprintf.m4
+++ b/gl/m4/vasnprintf.m4
@@ -1,5 +1,5 @@
-# vasnprintf.m4 serial 36
-dnl Copyright (C) 2002-2004, 2006-2013 Free Software Foundation, Inc.
+# vasnprintf.m4 serial 38
+dnl Copyright (C) 2002-2004, 2006-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -32,7 +32,6 @@ AC_DEFUN([gl_REPLACE_VASNPRINTF],
 # Prerequisites of lib/printf-args.h, lib/printf-args.c.
 AC_DEFUN([gl_PREREQ_PRINTF_ARGS],
 [
-  AC_REQUIRE([AC_TYPE_LONG_LONG_INT])
   AC_REQUIRE([gt_TYPE_WCHAR_T])
   AC_REQUIRE([gt_TYPE_WINT_T])
 ])
@@ -41,7 +40,6 @@ AC_DEFUN([gl_PREREQ_PRINTF_ARGS],
 AC_DEFUN([gl_PREREQ_PRINTF_PARSE],
 [
   AC_REQUIRE([gl_FEATURES_H])
-  AC_REQUIRE([AC_TYPE_LONG_LONG_INT])
   AC_REQUIRE([gt_TYPE_WCHAR_T])
   AC_REQUIRE([gt_TYPE_WINT_T])
   AC_REQUIRE([AC_TYPE_SIZE_T])
@@ -56,7 +54,6 @@ AC_DEFUN([gl_PREREQ_PRINTF_PARSE],
 AC_DEFUN_ONCE([gl_PREREQ_VASNPRINTF],
 [
   AC_REQUIRE([AC_FUNC_ALLOCA])
-  AC_REQUIRE([AC_TYPE_LONG_LONG_INT])
   AC_REQUIRE([gt_TYPE_WCHAR_T])
   AC_REQUIRE([gt_TYPE_WINT_T])
   AC_CHECK_FUNCS([snprintf strnlen wcslen wcsnlen mbrtowc wcrtomb])
@@ -77,6 +74,16 @@ AC_DEFUN_ONCE([gl_PREREQ_VASNPRINTF],
          if the buffer had been large enough.])
       ;;
   esac
+  dnl Additionally, the use of %n can be eliminated by assuming that snprintf
+  dnl always produces NUL-terminated strings (no truncation).
+  AC_REQUIRE([gl_SNPRINTF_TRUNCATION_C99])
+  case "$gl_cv_func_snprintf_truncation_c99" in
+    *yes)
+      AC_DEFINE([HAVE_SNPRINTF_TRUNCATION_C99], [1],
+        [Define if the string produced by the snprintf function is always NUL
+         terminated.])
+      ;;
+  esac
 ])
 
 # Extra prerequisites of lib/vasnprintf.c for supporting 'long double'
diff --git a/gl/m4/vasprintf.m4 b/gl/m4/vasprintf.m4
index c214ff11..6e6156a7 100644
--- a/gl/m4/vasprintf.m4
+++ b/gl/m4/vasprintf.m4
@@ -1,5 +1,5 @@
 # vasprintf.m4 serial 6
-dnl Copyright (C) 2002-2003, 2006-2007, 2009-2013 Free Software Foundation,
+dnl Copyright (C) 2002-2003, 2006-2007, 2009-2023 Free Software Foundation,
 dnl Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
diff --git a/gl/m4/visibility.m4 b/gl/m4/visibility.m4
index 6cbd7e5f..f0468e89 100644
--- a/gl/m4/visibility.m4
+++ b/gl/m4/visibility.m4
@@ -1,5 +1,5 @@
-# visibility.m4 serial 5 (gettext-0.18.2)
-dnl Copyright (C) 2005, 2008, 2010-2013 Free Software Foundation, Inc.
+# visibility.m4 serial 8
+dnl Copyright (C) 2005, 2008, 2010-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -29,42 +29,47 @@ AC_DEFUN([gl_VISIBILITY],
     dnl First, check whether -Werror can be added to the command line, or
     dnl whether it leads to an error because of some other option that the
     dnl user has put into $CC $CFLAGS $CPPFLAGS.
-    AC_MSG_CHECKING([whether the -Werror option is usable])
-    AC_CACHE_VAL([gl_cv_cc_vis_werror], [
-      gl_save_CFLAGS="$CFLAGS"
-      CFLAGS="$CFLAGS -Werror"
-      AC_COMPILE_IFELSE(
-        [AC_LANG_PROGRAM([[]], [[]])],
-        [gl_cv_cc_vis_werror=yes],
-        [gl_cv_cc_vis_werror=no])
-      CFLAGS="$gl_save_CFLAGS"])
-    AC_MSG_RESULT([$gl_cv_cc_vis_werror])
+    AC_CACHE_CHECK([whether the -Werror option is usable],
+      [gl_cv_cc_vis_werror],
+      [gl_save_CFLAGS="$CFLAGS"
+       CFLAGS="$CFLAGS -Werror"
+       AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[]], [[]])],
+         [gl_cv_cc_vis_werror=yes],
+         [gl_cv_cc_vis_werror=no])
+       CFLAGS="$gl_save_CFLAGS"
+      ])
     dnl Now check whether visibility declarations are supported.
-    AC_MSG_CHECKING([for simple visibility declarations])
-    AC_CACHE_VAL([gl_cv_cc_visibility], [
-      gl_save_CFLAGS="$CFLAGS"
-      CFLAGS="$CFLAGS -fvisibility=hidden"
-      dnl We use the option -Werror and a function dummyfunc, because on some
-      dnl platforms (Cygwin 1.7) the use of -fvisibility triggers a warning
-      dnl "visibility attribute not supported in this configuration; ignored"
-      dnl at the first function definition in every compilation unit, and we
-      dnl don't want to use the option in this case.
-      if test $gl_cv_cc_vis_werror = yes; then
-        CFLAGS="$CFLAGS -Werror"
-      fi
-      AC_COMPILE_IFELSE(
-        [AC_LANG_PROGRAM(
-           [[extern __attribute__((__visibility__("hidden"))) int hiddenvar;
-             extern __attribute__((__visibility__("default"))) int exportedvar;
-             extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void);
-             extern __attribute__((__visibility__("default"))) int exportedfunc (void);
-             void dummyfunc (void) {}
-           ]],
-           [[]])],
-        [gl_cv_cc_visibility=yes],
-        [gl_cv_cc_visibility=no])
-      CFLAGS="$gl_save_CFLAGS"])
-    AC_MSG_RESULT([$gl_cv_cc_visibility])
+    AC_CACHE_CHECK([for simple visibility declarations],
+      [gl_cv_cc_visibility],
+      [gl_save_CFLAGS="$CFLAGS"
+       CFLAGS="$CFLAGS -fvisibility=hidden"
+       dnl We use the option -Werror and a function dummyfunc, because on some
+       dnl platforms (Cygwin 1.7) the use of -fvisibility triggers a warning
+       dnl "visibility attribute not supported in this configuration; ignored"
+       dnl at the first function definition in every compilation unit, and we
+       dnl don't want to use the option in this case.
+       if test $gl_cv_cc_vis_werror = yes; then
+         CFLAGS="$CFLAGS -Werror"
+       fi
+       AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[extern __attribute__((__visibility__("hidden"))) int hiddenvar;
+              extern __attribute__((__visibility__("default"))) int exportedvar;
+              extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void);
+              extern __attribute__((__visibility__("default"))) int exportedfunc (void);
+              void dummyfunc (void);
+              int hiddenvar;
+              int exportedvar;
+              int hiddenfunc (void) { return 51; }
+              int exportedfunc (void) { return 1225736919; }
+              void dummyfunc (void) {}
+            ]],
+            [[]])],
+         [gl_cv_cc_visibility=yes],
+         [gl_cv_cc_visibility=no])
+       CFLAGS="$gl_save_CFLAGS"
+      ])
     if test $gl_cv_cc_visibility = yes; then
       CFLAG_VISIBILITY="-fvisibility=hidden"
       HAVE_VISIBILITY=1
diff --git a/gl/m4/vsnprintf.m4 b/gl/m4/vsnprintf.m4
index 4900764e..7fbb11c4 100644
--- a/gl/m4/vsnprintf.m4
+++ b/gl/m4/vsnprintf.m4
@@ -1,5 +1,5 @@
-# vsnprintf.m4 serial 6
-dnl Copyright (C) 2002-2004, 2007-2013 Free Software Foundation, Inc.
+# vsnprintf.m4 serial 7
+dnl Copyright (C) 2002-2004, 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -46,6 +46,14 @@ AC_DEFUN([gl_REPLACE_VSNPRINTF],
   AC_LIBOBJ([vsnprintf])
   if test $ac_cv_func_vsnprintf = yes; then
     REPLACE_VSNPRINTF=1
+  else
+    AC_CHECK_DECLS_ONCE([vsnprintf])
+    if test $ac_cv_have_decl_vsnprintf = yes; then
+      dnl If the function is declared but does not appear to exist, it may be
+      dnl defined as an inline function. In order to avoid a conflict, we have
+      dnl to define rpl_vsnprintf, not vsnprintf.
+      REPLACE_VSNPRINTF=1
+    fi
   fi
   gl_PREREQ_VSNPRINTF
 ])
diff --git a/gl/m4/warn-on-use.m4 b/gl/m4/warn-on-use.m4
index e43beebd..10649c5c 100644
--- a/gl/m4/warn-on-use.m4
+++ b/gl/m4/warn-on-use.m4
@@ -1,11 +1,13 @@
-# warn-on-use.m4 serial 5
-dnl Copyright (C) 2010-2013 Free Software Foundation, Inc.
+# warn-on-use.m4 serial 10
+dnl Copyright (C) 2010-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 # gl_WARN_ON_USE_PREPARE(INCLUDES, NAMES)
 # ---------------------------------------
+# If the module 'posixcheck' is in use:
+#
 # For each whitespace-separated element in the list of NAMES, define
 # HAVE_RAW_DECL_name if the function has a declaration among INCLUDES
 # even after being undefined as a macro.
@@ -23,25 +25,38 @@ dnl with or without modifications, as long as this notice is preserved.
 # needing gl_WARN_ON_USE_PREPARE.
 AC_DEFUN([gl_WARN_ON_USE_PREPARE],
 [
-  m4_foreach_w([gl_decl], [$2],
-    [AH_TEMPLATE([HAVE_RAW_DECL_]AS_TR_CPP(m4_defn([gl_decl])),
-      [Define to 1 if ]m4_defn([gl_decl])[ is declared even after
-       undefining macros.])])dnl
-dnl FIXME: gl_Symbol must be used unquoted until we can assume
-dnl autoconf 2.64 or newer.
-  for gl_func in m4_flatten([$2]); do
-    AS_VAR_PUSHDEF([gl_Symbol], [gl_cv_have_raw_decl_$gl_func])dnl
-    AC_CACHE_CHECK([whether $gl_func is declared without a macro],
-      gl_Symbol,
-      [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([$1],
-[@%:@undef $gl_func
-  (void) $gl_func;])],
-        [AS_VAR_SET(gl_Symbol, [yes])], [AS_VAR_SET(gl_Symbol, [no])])])
-    AS_VAR_IF(gl_Symbol, [yes],
-      [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_RAW_DECL_$gl_func]), [1])
-       dnl shortcut - if the raw declaration exists, then set a cache
-       dnl variable to allow skipping any later AC_CHECK_DECL efforts
-       eval ac_cv_have_decl_$gl_func=yes])
-    AS_VAR_POPDEF([gl_Symbol])dnl
-  done
+  m4_ifdef([gl_POSIXCHECK],
+    [m4_foreach_w([gl_decl], [$2],
+       [AH_TEMPLATE([HAVE_RAW_DECL_]AS_TR_CPP(m4_defn([gl_decl])),
+         [Define to 1 if ]m4_defn([gl_decl])[ is declared even after
+          undefining macros.])])dnl
+     for gl_func in m4_flatten([$2]); do
+       AS_VAR_PUSHDEF([gl_Symbol], [gl_cv_have_raw_decl_$gl_func])dnl
+       dnl As a workaround to implicit built-in function declarations in
+       dnl clang (e.g. strndup), reference ac_compile_for_check_decl instead
+       dnl of ac_compile.  If, for whatever reason, the override of AC_PROG_CC
+       dnl in zzgnulib.m4 is inactive, use the original ac_compile.
+       ac_save_ac_compile="$ac_compile"
+       if test -n "$ac_compile_for_check_decl"; then
+         ac_compile="$ac_compile_for_check_decl"
+       fi
+       AC_CACHE_CHECK([whether $gl_func is declared without a macro],
+         [gl_Symbol],
+         [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([$1],
+[[#undef $gl_func
+  (void) $gl_func;]])],
+           [AS_VAR_SET([gl_Symbol], [yes])], [AS_VAR_SET([gl_Symbol], [no])])])
+       ac_compile="$ac_save_ac_compile"
+       AS_VAR_IF([gl_Symbol], [yes],
+         [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_RAW_DECL_$gl_func]), [1])
+          dnl Shortcut for an AC_CHECK_DECL invocation that may come later:
+          dnl If the raw declaration exists with the given includes, then
+          dnl AC_CHECK_DECL with its many includes would see it as well.
+          dnl So, set a cache variable to allow skipping any later
+          dnl AC_CHECK_DECL invocation for $gl_func.
+          eval "ac_cv_have_decl_$gl_func=yes"
+         ])
+       AS_VAR_POPDEF([gl_Symbol])dnl
+     done
+    ])
 ])
diff --git a/gl/m4/wchar_h.m4 b/gl/m4/wchar_h.m4
index bedb15a4..8ec66193 100644
--- a/gl/m4/wchar_h.m4
+++ b/gl/m4/wchar_h.m4
@@ -1,15 +1,15 @@
 dnl A placeholder for ISO C99 <wchar.h>, for platforms that have issues.
 
-dnl Copyright (C) 2007-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl Written by Eric Blake.
 
-# wchar_h.m4 serial 39
+# wchar_h.m4 serial 55
 
-AC_DEFUN([gl_WCHAR_H],
+AC_DEFUN_ONCE([gl_WCHAR_H],
 [
   AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
   AC_REQUIRE([gl_WCHAR_H_INLINE_OK])
@@ -35,76 +35,82 @@ AC_DEFUN([gl_WCHAR_H],
   fi
   AC_SUBST([HAVE_WINT_T])
 
+  AC_REQUIRE([gl_TYPE_WINT_T_PREREQ])
+
   dnl Check for declarations of anything we want to poison if the
   dnl corresponding gnulib module is not in use.
   gl_WARN_ON_USE_PREPARE([[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#if !(defined __GLIBC__ && !defined __UCLIBC__)
-# include <stddef.h>
-# include <stdio.h>
-# include <time.h>
-#endif
-#include <wchar.h>
+      #include <wchar.h>
     ]],
     [btowc wctob mbsinit mbrtowc mbrlen mbsrtowcs mbsnrtowcs wcrtomb
-     wcsrtombs wcsnrtombs wcwidth wmemchr wmemcmp wmemcpy wmemmove wmemset
+     wcsrtombs wcsnrtombs wcwidth
+     wmemchr wmemcmp wmemcpy wmemmove wmempcpy wmemset
      wcslen wcsnlen wcscpy wcpcpy wcsncpy wcpncpy wcscat wcsncat wcscmp
      wcsncmp wcscasecmp wcsncasecmp wcscoll wcsxfrm wcsdup wcschr wcsrchr
-     wcscspn wcsspn wcspbrk wcsstr wcstok wcswidth
+     wcscspn wcsspn wcspbrk wcsstr wcstok wcswidth wcsftime
     ])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_CHECK_DECLS([wcsdup], [], [], [[
+      #include <wchar.h>
+    ]])
+  if test $ac_cv_have_decl_wcsdup = no; then
+    HAVE_DECL_WCSDUP=0
+  fi
 ])
 
 dnl Check whether <wchar.h> is usable at all.
 AC_DEFUN([gl_WCHAR_H_INLINE_OK],
 [
   dnl Test whether <wchar.h> suffers due to the transition from '__inline' to
-  dnl 'gnu_inline'. See <http://sourceware.org/bugzilla/show_bug.cgi?id=4022>
-  dnl and <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42440>. In summary,
+  dnl 'gnu_inline'. See <https://sourceware.org/bugzilla/show_bug.cgi?id=4022>
+  dnl and <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42440>. In summary,
   dnl glibc version 2.5 or older, together with gcc version 4.3 or newer and
   dnl the option -std=c99 or -std=gnu99, leads to a broken <wchar.h>.
+  AC_REQUIRE([AC_CANONICAL_HOST])
   AC_CACHE_CHECK([whether <wchar.h> uses 'inline' correctly],
     [gl_cv_header_wchar_h_correct_inline],
     [gl_cv_header_wchar_h_correct_inline=yes
-     AC_LANG_CONFTEST([
-       AC_LANG_SOURCE([[#define wcstod renamed_wcstod
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-extern int zero (void);
-int main () { return zero(); }
-]])])
-     if AC_TRY_EVAL([ac_compile]); then
-       mv conftest.$ac_objext conftest1.$ac_objext
-       AC_LANG_CONFTEST([
-         AC_LANG_SOURCE([[#define wcstod renamed_wcstod
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-int zero (void) { return 0; }
-]])])
-       if AC_TRY_EVAL([ac_compile]); then
-         mv conftest.$ac_objext conftest2.$ac_objext
-         if $CC -o conftest$ac_exeext $CFLAGS $LDFLAGS conftest1.$ac_objext conftest2.$ac_objext $LIBS >&AS_MESSAGE_LOG_FD 2>&1; then
-           :
-         else
-           gl_cv_header_wchar_h_correct_inline=no
+     case "$host_os" in
+       *-gnu* | gnu*)
+         AC_LANG_CONFTEST([
+           AC_LANG_SOURCE([[
+             #define wcstod renamed_wcstod
+             #include <wchar.h>
+             extern int zero (void);
+             int main () { return zero(); }
+           ]])])
+         dnl Do not rename the object file from conftest.$ac_objext to
+         dnl conftest1.$ac_objext, as this will cause the link to fail on
+         dnl z/OS when using the XPLINK object format (due to duplicate
+         dnl CSECT names). Instead, temporarily redefine $ac_compile so
+         dnl that the object file has the latter name from the start.
+         save_ac_compile="$ac_compile"
+         ac_compile=`echo "$save_ac_compile" | sed s/conftest/conftest1/`
+         if echo '#include "conftest.c"' >conftest1.c \
+            && AC_TRY_EVAL([ac_compile]); then
+           AC_LANG_CONFTEST([
+             AC_LANG_SOURCE([[
+               #define wcstod renamed_wcstod
+               #include <wchar.h>
+               int zero (void) { return 0; }
+             ]])])
+           dnl See note above about renaming object files.
+           ac_compile=`echo "$save_ac_compile" | sed s/conftest/conftest2/`
+           if echo '#include "conftest.c"' >conftest2.c \
+              && AC_TRY_EVAL([ac_compile]); then
+             if $CC -o conftest$ac_exeext $CFLAGS $LDFLAGS conftest1.$ac_objext conftest2.$ac_objext $LIBS >&AS_MESSAGE_LOG_FD 2>&1; then
+               :
+             else
+               gl_cv_header_wchar_h_correct_inline=no
+             fi
+           fi
          fi
-       fi
-     fi
-     rm -f conftest1.$ac_objext conftest2.$ac_objext conftest$ac_exeext
+         ac_compile="$save_ac_compile"
+         rm -f conftest[12].c conftest[12].$ac_objext conftest$ac_exeext
+         ;;
+     esac
     ])
   if test $gl_cv_header_wchar_h_correct_inline = no; then
     AC_MSG_ERROR([<wchar.h> cannot be used with this compiler ($CC $CFLAGS $CPPFLAGS).
@@ -112,63 +118,84 @@ This is a known interoperability problem of glibc <= 2.5 with gcc >= 4.3 in
 C99 mode. You have four options:
   - Add the flag -fgnu89-inline to CC and reconfigure, or
   - Fix your include files, using parts of
-    <http://sourceware.org/git/?p=glibc.git;a=commitdiff;h=b037a293a48718af30d706c2e18c929d0e69a621>, or
+    <https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=b037a293a48718af30d706c2e18c929d0e69a621>, or
   - Use a gcc version older than 4.3, or
   - Don't use the flags -std=c99 or -std=gnu99.
 Configuration aborted.])
   fi
 ])
 
+# gl_WCHAR_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_WCHAR_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_WCHAR_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_WCHAR_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_WCHAR_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_BTOWC])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCTOB])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSINIT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBRTOWC])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBRLEN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSRTOWCS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSNRTOWCS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCRTOMB])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSRTOMBS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSNRTOMBS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCWIDTH])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WMEMCHR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WMEMCMP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WMEMCPY])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WMEMMOVE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WMEMPCPY])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WMEMSET])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSLEN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSNLEN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSCPY])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCPCPY])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSNCPY])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCPNCPY])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSCAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSNCAT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSCMP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSNCMP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSCASECMP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSNCASECMP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSCOLL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSXFRM])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSDUP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSCHR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSRCHR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSCSPN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSSPN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSPBRK])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSSTR])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSTOK])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSWIDTH])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCSFTIME])
+    dnl Support Microsoft deprecated alias function names by default.
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MDA_WCSDUP], [1])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_WCHAR_H_MODULE_INDICATOR_DEFAULTS])
+  dnl Make sure the shell variable for GNULIB_FREE_POSIX is initialized.
+  gl_STDLIB_H_REQUIRE_DEFAULTS
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_WCHAR_H_DEFAULTS],
 [
-  GNULIB_BTOWC=0;       AC_SUBST([GNULIB_BTOWC])
-  GNULIB_WCTOB=0;       AC_SUBST([GNULIB_WCTOB])
-  GNULIB_MBSINIT=0;     AC_SUBST([GNULIB_MBSINIT])
-  GNULIB_MBRTOWC=0;     AC_SUBST([GNULIB_MBRTOWC])
-  GNULIB_MBRLEN=0;      AC_SUBST([GNULIB_MBRLEN])
-  GNULIB_MBSRTOWCS=0;   AC_SUBST([GNULIB_MBSRTOWCS])
-  GNULIB_MBSNRTOWCS=0;  AC_SUBST([GNULIB_MBSNRTOWCS])
-  GNULIB_WCRTOMB=0;     AC_SUBST([GNULIB_WCRTOMB])
-  GNULIB_WCSRTOMBS=0;   AC_SUBST([GNULIB_WCSRTOMBS])
-  GNULIB_WCSNRTOMBS=0;  AC_SUBST([GNULIB_WCSNRTOMBS])
-  GNULIB_WCWIDTH=0;     AC_SUBST([GNULIB_WCWIDTH])
-  GNULIB_WMEMCHR=0;     AC_SUBST([GNULIB_WMEMCHR])
-  GNULIB_WMEMCMP=0;     AC_SUBST([GNULIB_WMEMCMP])
-  GNULIB_WMEMCPY=0;     AC_SUBST([GNULIB_WMEMCPY])
-  GNULIB_WMEMMOVE=0;    AC_SUBST([GNULIB_WMEMMOVE])
-  GNULIB_WMEMSET=0;     AC_SUBST([GNULIB_WMEMSET])
-  GNULIB_WCSLEN=0;      AC_SUBST([GNULIB_WCSLEN])
-  GNULIB_WCSNLEN=0;     AC_SUBST([GNULIB_WCSNLEN])
-  GNULIB_WCSCPY=0;      AC_SUBST([GNULIB_WCSCPY])
-  GNULIB_WCPCPY=0;      AC_SUBST([GNULIB_WCPCPY])
-  GNULIB_WCSNCPY=0;     AC_SUBST([GNULIB_WCSNCPY])
-  GNULIB_WCPNCPY=0;     AC_SUBST([GNULIB_WCPNCPY])
-  GNULIB_WCSCAT=0;      AC_SUBST([GNULIB_WCSCAT])
-  GNULIB_WCSNCAT=0;     AC_SUBST([GNULIB_WCSNCAT])
-  GNULIB_WCSCMP=0;      AC_SUBST([GNULIB_WCSCMP])
-  GNULIB_WCSNCMP=0;     AC_SUBST([GNULIB_WCSNCMP])
-  GNULIB_WCSCASECMP=0;  AC_SUBST([GNULIB_WCSCASECMP])
-  GNULIB_WCSNCASECMP=0; AC_SUBST([GNULIB_WCSNCASECMP])
-  GNULIB_WCSCOLL=0;     AC_SUBST([GNULIB_WCSCOLL])
-  GNULIB_WCSXFRM=0;     AC_SUBST([GNULIB_WCSXFRM])
-  GNULIB_WCSDUP=0;      AC_SUBST([GNULIB_WCSDUP])
-  GNULIB_WCSCHR=0;      AC_SUBST([GNULIB_WCSCHR])
-  GNULIB_WCSRCHR=0;     AC_SUBST([GNULIB_WCSRCHR])
-  GNULIB_WCSCSPN=0;     AC_SUBST([GNULIB_WCSCSPN])
-  GNULIB_WCSSPN=0;      AC_SUBST([GNULIB_WCSSPN])
-  GNULIB_WCSPBRK=0;     AC_SUBST([GNULIB_WCSPBRK])
-  GNULIB_WCSSTR=0;      AC_SUBST([GNULIB_WCSSTR])
-  GNULIB_WCSTOK=0;      AC_SUBST([GNULIB_WCSTOK])
-  GNULIB_WCSWIDTH=0;    AC_SUBST([GNULIB_WCSWIDTH])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_BTOWC=1;         AC_SUBST([HAVE_BTOWC])
   HAVE_MBSINIT=1;       AC_SUBST([HAVE_MBSINIT])
@@ -183,6 +210,7 @@ AC_DEFUN([gl_WCHAR_H_DEFAULTS],
   HAVE_WMEMCMP=1;       AC_SUBST([HAVE_WMEMCMP])
   HAVE_WMEMCPY=1;       AC_SUBST([HAVE_WMEMCPY])
   HAVE_WMEMMOVE=1;      AC_SUBST([HAVE_WMEMMOVE])
+  HAVE_WMEMPCPY=1;      AC_SUBST([HAVE_WMEMPCPY])
   HAVE_WMEMSET=1;       AC_SUBST([HAVE_WMEMSET])
   HAVE_WCSLEN=1;        AC_SUBST([HAVE_WCSLEN])
   HAVE_WCSNLEN=1;       AC_SUBST([HAVE_WCSNLEN])
@@ -207,7 +235,9 @@ AC_DEFUN([gl_WCHAR_H_DEFAULTS],
   HAVE_WCSSTR=1;        AC_SUBST([HAVE_WCSSTR])
   HAVE_WCSTOK=1;        AC_SUBST([HAVE_WCSTOK])
   HAVE_WCSWIDTH=1;      AC_SUBST([HAVE_WCSWIDTH])
+  HAVE_WCSFTIME=1;      AC_SUBST([HAVE_WCSFTIME])
   HAVE_DECL_WCTOB=1;    AC_SUBST([HAVE_DECL_WCTOB])
+  HAVE_DECL_WCSDUP=1;   AC_SUBST([HAVE_DECL_WCSDUP])
   HAVE_DECL_WCWIDTH=1;  AC_SUBST([HAVE_DECL_WCWIDTH])
   REPLACE_MBSTATE_T=0;  AC_SUBST([REPLACE_MBSTATE_T])
   REPLACE_BTOWC=0;      AC_SUBST([REPLACE_BTOWC])
@@ -222,4 +252,6 @@ AC_DEFUN([gl_WCHAR_H_DEFAULTS],
   REPLACE_WCSNRTOMBS=0; AC_SUBST([REPLACE_WCSNRTOMBS])
   REPLACE_WCWIDTH=0;    AC_SUBST([REPLACE_WCWIDTH])
   REPLACE_WCSWIDTH=0;   AC_SUBST([REPLACE_WCSWIDTH])
+  REPLACE_WCSFTIME=0;   AC_SUBST([REPLACE_WCSFTIME])
+  REPLACE_WCSTOK=0;     AC_SUBST([REPLACE_WCSTOK])
 ])
diff --git a/gl/m4/wchar_t.m4 b/gl/m4/wchar_t.m4
index e1e1e699..50bde08a 100644
--- a/gl/m4/wchar_t.m4
+++ b/gl/m4/wchar_t.m4
@@ -1,5 +1,5 @@
 # wchar_t.m4 serial 4 (gettext-0.18.2)
-dnl Copyright (C) 2002-2003, 2008-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2002-2003, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/wcrtomb.m4 b/gl/m4/wcrtomb.m4
index f56b5bae..d51b36e1 100644
--- a/gl/m4/wcrtomb.m4
+++ b/gl/m4/wcrtomb.m4
@@ -1,5 +1,5 @@
-# wcrtomb.m4 serial 11
-dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
+# wcrtomb.m4 serial 17
+dnl Copyright (C) 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -15,15 +15,8 @@ AC_DEFUN([gl_FUNC_WCRTOMB],
   if test $ac_cv_func_wcrtomb = no; then
     HAVE_WCRTOMB=0
     AC_CHECK_DECLS([wcrtomb],,, [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]])
+      #include <wchar.h>
+    ]])
     if test $ac_cv_have_decl_wcrtomb = yes; then
       dnl On Minix 3.1.8, the system's <wchar.h> declares wcrtomb() although
       dnl it does not have the function. Avoid a collision with gnulib's
@@ -31,17 +24,56 @@ AC_DEFUN([gl_FUNC_WCRTOMB],
       REPLACE_WCRTOMB=1
     fi
   else
-    if test $REPLACE_MBSTATE_T = 1; then
-      REPLACE_WCRTOMB=1
-    else
-      dnl On AIX 4.3, OSF/1 5.1 and Solaris 10, wcrtomb (NULL, 0, NULL) sometimes
-      dnl returns 0 instead of 1.
+    dnl We don't actually need to override wcrtomb when redefining the semantics
+    dnl of the mbstate_t type. Tested on 32-bit AIX.
+    dnl if test $REPLACE_MBSTATE_T = 1; then
+    dnl   REPLACE_WCRTOMB=1
+    dnl fi
+    if test $REPLACE_WCRTOMB = 0; then
+      dnl On Android 4.3, wcrtomb produces wrong characters in the C locale.
+      dnl On AIX 4.3, OSF/1 5.1 and Solaris <= 11.3, wcrtomb (NULL, 0, NULL)
+      dnl sometimes returns 0 instead of 1.
       AC_REQUIRE([AC_PROG_CC])
       AC_REQUIRE([gt_LOCALE_FR])
       AC_REQUIRE([gt_LOCALE_FR_UTF8])
       AC_REQUIRE([gt_LOCALE_JA])
       AC_REQUIRE([gt_LOCALE_ZH_CN])
       AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+      AC_CACHE_CHECK([whether wcrtomb works in the C locale],
+        [gl_cv_func_wcrtomb_works],
+        [AC_RUN_IFELSE(
+           [AC_LANG_SOURCE([[
+#include <string.h>
+#include <stdlib.h>
+#include <wchar.h>
+int main ()
+{
+  mbstate_t state;
+  char out[64];
+  int count;
+  memset (&state, 0, sizeof (state));
+  out[0] = 'x';
+  count = wcrtomb (out, L'a', &state);
+  return !(count == 1 && out[0] == 'a');
+}]])],
+           [gl_cv_func_wcrtomb_works=yes],
+           [gl_cv_func_wcrtomb_works=no],
+           [case "$host_os" in
+                               # Guess no on Android.
+              linux*-android*) gl_cv_func_wcrtomb_works="guessing no";;
+                               # Guess yes otherwise.
+              *)               gl_cv_func_wcrtomb_works="guessing yes";;
+            esac
+           ])
+        ])
+      case "$gl_cv_func_wcrtomb_works" in
+        *yes) ;;
+        *) AC_DEFINE([WCRTOMB_C_LOCALE_BUG], [1],
+             [Define if the wcrtomb function does not work in the C locale.])
+           REPLACE_WCRTOMB=1 ;;
+      esac
+    fi
+    if test $REPLACE_WCRTOMB = 0; then
       AC_CACHE_CHECK([whether wcrtomb return value is correct],
         [gl_cv_func_wcrtomb_retval],
         [
@@ -49,10 +81,10 @@ AC_DEFUN([gl_FUNC_WCRTOMB],
           dnl is present.
 changequote(,)dnl
           case "$host_os" in
-                                     # Guess no on AIX 4, OSF/1 and Solaris.
-            aix4* | osf* | solaris*) gl_cv_func_wcrtomb_retval="guessing no" ;;
-                                     # Guess yes otherwise.
-            *)                       gl_cv_func_wcrtomb_retval="guessing yes" ;;
+            # Guess no on AIX 4, OSF/1, Solaris, native Windows.
+            aix4* | osf* | solaris* | mingw*) gl_cv_func_wcrtomb_retval="guessing no" ;;
+            # Guess yes otherwise.
+            *)                                gl_cv_func_wcrtomb_retval="guessing yes" ;;
           esac
 changequote([,])dnl
           if test $LOCALE_FR != none || test $LOCALE_FR_UTF8 != none || test $LOCALE_JA != none || test $LOCALE_ZH_CN != none; then
@@ -60,14 +92,8 @@ changequote([,])dnl
               [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
+#include <stdlib.h>
 int main ()
 {
   int result = 0;
@@ -80,6 +106,12 @@ int main ()
     {
       if (wcrtomb (NULL, 0, NULL) != 1)
         result |= 2;
+      {
+        wchar_t wc = (wchar_t) 0xBADFACE;
+        if (mbtowc (&wc, "\303\274", 2) == 2)
+          if (wcrtomb (NULL, wc, NULL) != 1)
+            result |= 2;
+      }
     }
   if (setlocale (LC_ALL, "$LOCALE_JA") != NULL)
     {
@@ -100,7 +132,9 @@ int main ()
         ])
       case "$gl_cv_func_wcrtomb_retval" in
         *yes) ;;
-        *) REPLACE_WCRTOMB=1 ;;
+        *) AC_DEFINE([WCRTOMB_RETVAL_BUG], [1],
+             [Define if the wcrtomb function has an incorrect return value.])
+           REPLACE_WCRTOMB=1 ;;
       esac
     fi
   fi
diff --git a/gl/m4/wctype_h.m4 b/gl/m4/wctype_h.m4
index 82ada0ee..6856a735 100644
--- a/gl/m4/wctype_h.m4
+++ b/gl/m4/wctype_h.m4
@@ -1,15 +1,15 @@
-# wctype_h.m4 serial 18
+# wctype_h.m4 serial 30
 
 dnl A placeholder for ISO C99 <wctype.h>, for platforms that lack it.
 
-dnl Copyright (C) 2006-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2006-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl Written by Paul Eggert.
 
-AC_DEFUN([gl_WCTYPE_H],
+AC_DEFUN_ONCE([gl_WCTYPE_H],
 [
   AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
   AC_REQUIRE([AC_PROG_CC])
@@ -30,6 +30,8 @@ AC_DEFUN([gl_WCTYPE_H],
   fi
   AC_SUBST([HAVE_WINT_T])
 
+  AC_REQUIRE([gl_TYPE_WINT_T_PREREQ])
+
   gl_CHECK_NEXT_HEADERS([wctype.h])
   if test $ac_cv_header_wctype_h = yes; then
     if test $ac_cv_func_iswcntrl = yes; then
@@ -39,22 +41,16 @@ AC_DEFUN([gl_WCTYPE_H],
         [
           AC_RUN_IFELSE(
             [AC_LANG_SOURCE([[
-               /* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
-                  included before <wchar.h>.
-                  BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
-                  must be included before <wchar.h>.  */
-               #include <stddef.h>
-               #include <stdio.h>
-               #include <time.h>
                #include <wchar.h>
                #include <wctype.h>
                int main () { return iswprint ('x') == 0; }
             ]])],
             [gl_cv_func_iswcntrl_works=yes], [gl_cv_func_iswcntrl_works=no],
-            [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stdlib.h>
+            [dnl Guess no on Linux libc5, yes otherwise.
+             AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stdlib.h>
                           #if __GNU_LIBRARY__ == 1
                           Linux libc5 i18n is broken.
-                          #endif]], [])],
+                          #endif]], [[]])],
               [gl_cv_func_iswcntrl_works="guessing yes"],
               [gl_cv_func_iswcntrl_works="guessing no"])
             ])
@@ -66,10 +62,14 @@ AC_DEFUN([gl_WCTYPE_H],
   fi
   AC_SUBST([HAVE_WCTYPE_H])
 
-  case "$gl_cv_func_iswcntrl_works" in
-    *yes) REPLACE_ISWCNTRL=0 ;;
-    *)    REPLACE_ISWCNTRL=1 ;;
-  esac
+  if test $GNULIBHEADERS_OVERRIDE_WINT_T = 1; then
+    REPLACE_ISWCNTRL=1
+  else
+    case "$gl_cv_func_iswcntrl_works" in
+      *yes) REPLACE_ISWCNTRL=0 ;;
+      *)    REPLACE_ISWCNTRL=1 ;;
+    esac
+  fi
   AC_SUBST([REPLACE_ISWCNTRL])
 
   if test $HAVE_ISWCNTRL = 0 || test $REPLACE_ISWCNTRL = 1; then
@@ -85,14 +85,7 @@ AC_DEFUN([gl_WCTYPE_H],
       REPLACE_TOWLOWER=0
     else
       AC_CHECK_DECLS([towlower],,,
-        [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
-             included before <wchar.h>.
-             BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
-             must be included before <wchar.h>.  */
-          #include <stddef.h>
-          #include <stdio.h>
-          #include <time.h>
-          #include <wchar.h>
+        [[#include <wchar.h>
           #if HAVE_WCTYPE_H
           # include <wctype.h>
           #endif
@@ -121,14 +114,7 @@ AC_DEFUN([gl_WCTYPE_H],
   AC_CACHE_CHECK([for wctype_t], [gl_cv_type_wctype_t],
     [AC_COMPILE_IFELSE(
        [AC_LANG_PROGRAM(
-          [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
-               included before <wchar.h>.
-               BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
-               must be included before <wchar.h>.  */
-            #include <stddef.h>
-            #include <stdio.h>
-            #include <time.h>
-            #include <wchar.h>
+          [[#include <wchar.h>
             #if HAVE_WCTYPE_H
             # include <wctype.h>
             #endif
@@ -147,14 +133,7 @@ AC_DEFUN([gl_WCTYPE_H],
   AC_CACHE_CHECK([for wctrans_t], [gl_cv_type_wctrans_t],
     [AC_COMPILE_IFELSE(
        [AC_LANG_PROGRAM(
-          [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
-               included before <wchar.h>.
-               BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
-               must be included before <wchar.h>.  */
-            #include <stddef.h>
-            #include <stdio.h>
-            #include <time.h>
-            #include <wchar.h>
+          [[#include <wchar.h>
             #include <wctype.h>
             wctrans_t a;
           ]],
@@ -169,14 +148,7 @@ AC_DEFUN([gl_WCTYPE_H],
   dnl Check for declarations of anything we want to poison if the
   dnl corresponding gnulib module is not in use.
   gl_WARN_ON_USE_PREPARE([[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
 #if !(defined __GLIBC__ && !defined __UCLIBC__)
-# include <stddef.h>
-# include <stdio.h>
-# include <time.h>
 # include <wchar.h>
 #endif
 #include <wctype.h>
@@ -185,25 +157,44 @@ AC_DEFUN([gl_WCTYPE_H],
     ])
 ])
 
+# gl_WCTYPE_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_WCTYPE_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_WCTYPE_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_WCTYPE_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_WCTYPE_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISWBLANK])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISWDIGIT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISWXDIGIT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCTYPE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISWCTYPE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_WCTRANS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_TOWCTRANS])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_WCTYPE_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_WCTYPE_H_DEFAULTS],
 [
-  GNULIB_ISWBLANK=0;    AC_SUBST([GNULIB_ISWBLANK])
-  GNULIB_WCTYPE=0;      AC_SUBST([GNULIB_WCTYPE])
-  GNULIB_ISWCTYPE=0;    AC_SUBST([GNULIB_ISWCTYPE])
-  GNULIB_WCTRANS=0;     AC_SUBST([GNULIB_WCTRANS])
-  GNULIB_TOWCTRANS=0;   AC_SUBST([GNULIB_TOWCTRANS])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_ISWBLANK=1;      AC_SUBST([HAVE_ISWBLANK])
   HAVE_WCTYPE_T=1;      AC_SUBST([HAVE_WCTYPE_T])
   HAVE_WCTRANS_T=1;     AC_SUBST([HAVE_WCTRANS_T])
   REPLACE_ISWBLANK=0;   AC_SUBST([REPLACE_ISWBLANK])
+  REPLACE_ISWDIGIT=0;   AC_SUBST([REPLACE_ISWDIGIT])
+  REPLACE_ISWXDIGIT=0;  AC_SUBST([REPLACE_ISWXDIGIT])
 ])
diff --git a/gl/m4/wint_t.m4 b/gl/m4/wint_t.m4
index d7cd3db9..dfd743b3 100644
--- a/gl/m4/wint_t.m4
+++ b/gl/m4/wint_t.m4
@@ -1,11 +1,12 @@
-# wint_t.m4 serial 5 (gettext-0.18.2)
-dnl Copyright (C) 2003, 2007-2013 Free Software Foundation, Inc.
+# wint_t.m4 serial 11
+dnl Copyright (C) 2003, 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl From Bruno Haible.
-dnl Test whether <wchar.h> has the 'wint_t' type.
+dnl Test whether <wchar.h> has the 'wint_t' type and whether gnulib's
+dnl <wchar.h> or <wctype.h> would, if present, override 'wint_t'.
 dnl Prerequisite: AC_PROG_CC
 
 AC_DEFUN([gt_TYPE_WINT_T],
@@ -13,20 +14,44 @@ AC_DEFUN([gt_TYPE_WINT_T],
   AC_CACHE_CHECK([for wint_t], [gt_cv_c_wint_t],
     [AC_COMPILE_IFELSE(
        [AC_LANG_PROGRAM(
-          [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
-   before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
+          [[#include <wchar.h>
             wint_t foo = (wchar_t)'\0';]],
           [[]])],
        [gt_cv_c_wint_t=yes],
        [gt_cv_c_wint_t=no])])
   if test $gt_cv_c_wint_t = yes; then
     AC_DEFINE([HAVE_WINT_T], [1], [Define if you have the 'wint_t' type.])
+
+    dnl Determine whether gnulib's <wchar.h> or <wctype.h> would, if present,
+    dnl override 'wint_t'.
+    AC_CACHE_CHECK([whether wint_t is large enough],
+      [gl_cv_type_wint_t_large_enough],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <wchar.h>
+              int verify[sizeof (wint_t) < sizeof (int) ? -1 : 1];
+            ]])],
+         [gl_cv_type_wint_t_large_enough=yes],
+         [gl_cv_type_wint_t_large_enough=no])])
+    if test $gl_cv_type_wint_t_large_enough = no; then
+      GNULIBHEADERS_OVERRIDE_WINT_T=1
+    else
+      GNULIBHEADERS_OVERRIDE_WINT_T=0
+    fi
+  else
+    GNULIBHEADERS_OVERRIDE_WINT_T=0
+  fi
+  AC_SUBST([GNULIBHEADERS_OVERRIDE_WINT_T])
+])
+
+dnl Prerequisites of the 'wint_t' override.
+AC_DEFUN([gl_TYPE_WINT_T_PREREQ],
+[
+  AC_CHECK_HEADERS_ONCE([crtdefs.h])
+  if test $ac_cv_header_crtdefs_h = yes; then
+    HAVE_CRTDEFS_H=1
+  else
+    HAVE_CRTDEFS_H=0
   fi
+  AC_SUBST([HAVE_CRTDEFS_H])
 ])
diff --git a/gl/m4/xalloc.m4 b/gl/m4/xalloc.m4
index 64ca7014..fc56f59a 100644
--- a/gl/m4/xalloc.m4
+++ b/gl/m4/xalloc.m4
@@ -1,5 +1,5 @@
 # xalloc.m4 serial 18
-dnl Copyright (C) 2002-2006, 2009-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2002-2006, 2009-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/xsize.m4 b/gl/m4/xsize.m4
index 8ea9f2cd..649db9c5 100644
--- a/gl/m4/xsize.m4
+++ b/gl/m4/xsize.m4
@@ -1,5 +1,5 @@
 # xsize.m4 serial 5
-dnl Copyright (C) 2003-2004, 2008-2013 Free Software Foundation, Inc.
+dnl Copyright (C) 2003-2004, 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/gl/m4/xstrndup.m4 b/gl/m4/xstrndup.m4
deleted file mode 100644
index 4a9330bb..00000000
--- a/gl/m4/xstrndup.m4
+++ /dev/null
@@ -1,15 +0,0 @@
-# xstrndup.m4 serial 2
-dnl Copyright (C) 2003, 2009-2013 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-AC_DEFUN([gl_XSTRNDUP],
-[
-  gl_PREREQ_XSTRNDUP
-])
-
-# Prerequisites of lib/xstrndup.c.
-AC_DEFUN([gl_PREREQ_XSTRNDUP], [
-  :
-])
diff --git a/gl/m4/zzgnulib.m4 b/gl/m4/zzgnulib.m4
new file mode 100644
index 00000000..362102b6
--- /dev/null
+++ b/gl/m4/zzgnulib.m4
@@ -0,0 +1,23 @@
+# zzgnulib.m4 serial 1
+dnl Copyright (C) 2020-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl This file must be named something that sorts after all other
+dnl package- or gnulib-provided .m4 files - at least for those packages
+dnl that redefine AC_PROG_CC.
+
+dnl Redefine AC_PROG_CC so that it ends with invocations of gl_COMPILER_CLANG
+dnl and gl_COMPILER_PREPARE_CHECK_DECL.
+m4_define([AC_PROG_CC],
+  m4_defn([AC_PROG_CC])[
+gl_COMPILER_CLANG
+gl_COMPILER_PREPARE_CHECK_DECL
+])
+
+# gl_ZZGNULIB
+# -----------
+# Witness macro that this file has been included.  Needed to force
+# Automake to include this file after all other gnulib .m4 files.
+AC_DEFUN([gl_ZZGNULIB])