1 files changed, 78 insertions, 18 deletions

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\"") \