11 files changed, 163 insertions, 69 deletions

diff --git a/gl/Makefile.am b/gl/Makefile.am
index e9e23026..edc7db15 100644
--- a/gl/Makefile.am
+++ b/gl/Makefile.am
@@ -1182,6 +1182,7 @@ stdlib.h: stdlib.in.h $(CXXDEFS_H) $(ARG_NONNULL_H) $(WARN_ON_USE_H)
           sed -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
               -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
               -e 's|@''NEXT_STDLIB_H''@|$(NEXT_STDLIB_H)|g' \
+              -e 's|@''GNULIB__EXIT''@|$(GNULIB__EXIT)|g' \
               -e 's|@''GNULIB_ATOLL''@|$(GNULIB_ATOLL)|g' \
               -e 's|@''GNULIB_CALLOC_POSIX''@|$(GNULIB_CALLOC_POSIX)|g' \
               -e 's|@''GNULIB_CANONICALIZE_FILE_NAME''@|$(GNULIB_CANONICALIZE_FILE_NAME)|g' \
@@ -1206,13 +1207,12 @@ stdlib.h: stdlib.in.h $(CXXDEFS_H) $(ARG_NONNULL_H) $(WARN_ON_USE_H)
               -e 's|@''GNULIB_STRTOULL''@|$(GNULIB_STRTOULL)|g' \
               -e 's|@''GNULIB_UNLOCKPT''@|$(GNULIB_UNLOCKPT)|g' \
               -e 's|@''GNULIB_UNSETENV''@|$(GNULIB_UNSETENV)|g' \
+              -e 's|@''HAVE__EXIT''@|$(HAVE__EXIT)|g' \
               -e 's|@''HAVE_ATOLL''@|$(HAVE_ATOLL)|g' \
-              -e 's|@''HAVE_CALLOC_POSIX''@|$(HAVE_CALLOC_POSIX)|g' \
               -e 's|@''HAVE_CANONICALIZE_FILE_NAME''@|$(HAVE_CANONICALIZE_FILE_NAME)|g' \
               -e 's|@''HAVE_DECL_GETLOADAVG''@|$(HAVE_DECL_GETLOADAVG)|g' \
               -e 's|@''HAVE_GETSUBOPT''@|$(HAVE_GETSUBOPT)|g' \
               -e 's|@''HAVE_GRANTPT''@|$(HAVE_GRANTPT)|g' \
-              -e 's|@''HAVE_MALLOC_POSIX''@|$(HAVE_MALLOC_POSIX)|g' \
               -e 's|@''HAVE_MKDTEMP''@|$(HAVE_MKDTEMP)|g' \
               -e 's|@''HAVE_MKOSTEMP''@|$(HAVE_MKOSTEMP)|g' \
               -e 's|@''HAVE_MKOSTEMPS''@|$(HAVE_MKOSTEMPS)|g' \
@@ -1221,7 +1221,6 @@ stdlib.h: stdlib.in.h $(CXXDEFS_H) $(ARG_NONNULL_H) $(WARN_ON_USE_H)
               -e 's|@''HAVE_PTSNAME''@|$(HAVE_PTSNAME)|g' \
               -e 's|@''HAVE_RANDOM_H''@|$(HAVE_RANDOM_H)|g' \
               -e 's|@''HAVE_RANDOM_R''@|$(HAVE_RANDOM_R)|g' \
-              -e 's|@''HAVE_REALLOC_POSIX''@|$(HAVE_REALLOC_POSIX)|g' \
               -e 's|@''HAVE_REALPATH''@|$(HAVE_REALPATH)|g' \
               -e 's|@''HAVE_RPMATCH''@|$(HAVE_RPMATCH)|g' \
               -e 's|@''HAVE_SETENV''@|$(HAVE_SETENV)|g' \
@@ -1232,9 +1231,12 @@ stdlib.h: stdlib.in.h $(CXXDEFS_H) $(ARG_NONNULL_H) $(WARN_ON_USE_H)
               -e 's|@''HAVE_SYS_LOADAVG_H''@|$(HAVE_SYS_LOADAVG_H)|g' \
               -e 's|@''HAVE_UNLOCKPT''@|$(HAVE_UNLOCKPT)|g' \
               -e 's|@''HAVE_UNSETENV''@|$(HAVE_UNSETENV)|g' \
+              -e 's|@''REPLACE_CALLOC''@|$(REPLACE_CALLOC)|g' \
               -e 's|@''REPLACE_CANONICALIZE_FILE_NAME''@|$(REPLACE_CANONICALIZE_FILE_NAME)|g' \
+              -e 's|@''REPLACE_MALLOC''@|$(REPLACE_MALLOC)|g' \
               -e 's|@''REPLACE_MKSTEMP''@|$(REPLACE_MKSTEMP)|g' \
               -e 's|@''REPLACE_PUTENV''@|$(REPLACE_PUTENV)|g' \
+              -e 's|@''REPLACE_REALLOC''@|$(REPLACE_REALLOC)|g' \
               -e 's|@''REPLACE_REALPATH''@|$(REPLACE_REALPATH)|g' \
               -e 's|@''REPLACE_SETENV''@|$(REPLACE_SETENV)|g' \
               -e 's|@''REPLACE_STRTOD''@|$(REPLACE_STRTOD)|g' \
diff --git a/gl/fsusage.c b/gl/fsusage.c
index 10db467d..17102aad 100644
--- a/gl/fsusage.c
+++ b/gl/fsusage.c
@@ -94,7 +94,7 @@
 int
 get_fs_usage (char const *file, char const *disk, struct fs_usage *fsp)
 {
-#if defined STAT_STATVFS                /* POSIX */
+#if defined STAT_STATVFS                /* POSIX, except glibc/Linux */
 
   struct statvfs fsd;
 
@@ -156,7 +156,7 @@ get_fs_usage (char const *file, char const *disk, struct fs_usage *fsp)
                     : (fsd.s_isize - 2) * INOPB * (fsd.s_type == Fs2b ? 2 : 1));
   fsp->fsu_ffree = PROPAGATE_ALL_ONES (fsd.s_tinode);
 
-#elif defined STAT_STATFS3_OSF1
+#elif defined STAT_STATFS3_OSF1         /* OSF/1 */
 
   struct statfs fsd;
 
@@ -165,7 +165,9 @@ get_fs_usage (char const *file, char const *disk, struct fs_usage *fsp)
 
   fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_fsize);
 
-#elif defined STAT_STATFS2_BSIZE        /* 4.3BSD, SunOS 4, HP-UX, AIX */
+#elif defined STAT_STATFS2_BSIZE        /* glibc/Linux, 4.3BSD, SunOS 4, \
+                                           MacOS X < 10.4, FreeBSD < 5.0, \
+                                           NetBSD < 3.0, OpenBSD < 4.4 */
 
   struct statfs fsd;
 
@@ -189,7 +191,7 @@ get_fs_usage (char const *file, char const *disk, struct fs_usage *fsp)
     }
 # endif /* STATFS_TRUNCATES_BLOCK_COUNTS */
 
-#elif defined STAT_STATFS2_FSIZE        /* 4.4BSD */
+#elif defined STAT_STATFS2_FSIZE        /* 4.4BSD and older NetBSD */
 
   struct statfs fsd;
 
@@ -198,7 +200,8 @@ get_fs_usage (char const *file, char const *disk, struct fs_usage *fsp)
 
   fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_fsize);
 
-#elif defined STAT_STATFS4              /* SVR3, Dynix, Irix, AIX */
+#elif defined STAT_STATFS4              /* SVR3, Dynix, old Irix, old AIX, \
+                                           Dolphin */
 
 # if !_AIX && !defined _SEQUENT_ && !defined DOLPHIN
 #  define f_bavail f_bfree
diff --git a/gl/m4/fcntl-o.m4 b/gl/m4/fcntl-o.m4
index d416a61c..1adacc8a 100644
--- a/gl/m4/fcntl-o.m4
+++ b/gl/m4/fcntl-o.m4
@@ -1,4 +1,4 @@
-# fcntl-o.m4 serial 1
+# fcntl-o.m4 serial 2
 dnl Copyright (C) 2006, 2009-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -12,7 +12,11 @@ dnl Written by Paul Eggert.
 AC_DEFUN([gl_FCNTL_O_FLAGS],
 [
   dnl Persuade glibc <fcntl.h> to define O_NOATIME and O_NOFOLLOW.
-  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+  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_CACHE_CHECK([for working fcntl.h], [gl_cv_header_working_fcntl_h],
     [AC_RUN_IFELSE(
        [AC_LANG_PROGRAM(
diff --git a/gl/m4/fsusage.m4 b/gl/m4/fsusage.m4
index 216b9dd8..68684c27 100644
--- a/gl/m4/fsusage.m4
+++ b/gl/m4/fsusage.m4
@@ -1,4 +1,4 @@
-# serial 25
+# serial 26
 # Obtaining file system usage information.
 
 # Copyright (C) 1997-1998, 2000-2001, 2003-2010 Free Software Foundation, Inc.
@@ -44,7 +44,8 @@ ac_fsusage_space=no
 # 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
-  # SVR4
+  # glibc/{Hurd,kFreeBSD}, MacOS X >= 10.4, 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>
 #if defined __GLIBC__ && defined __linux__
@@ -97,8 +98,13 @@ if test $ac_fsusage_space = no; then
 fi
 
 if test $ac_fsusage_space = no; then
-# AIX
-  AC_MSG_CHECKING([for two-argument statfs with statfs.bsize dnl
+  # glibc/Linux, MacOS X < 10.4, FreeBSD < 5.0, NetBSD < 3.0, OpenBSD < 4.4.
+  # (glibc/{Hurd,kFreeBSD}, MacOS X >= 10.4, 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([[
@@ -131,7 +137,8 @@ member (AIX, 4.3BSD)])
 fi
 
 if test $ac_fsusage_space = no; then
-# SVR3
+  # 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([[
@@ -150,13 +157,17 @@ if test $ac_fsusage_space = no; then
   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, Irix, Dolphin)])
+      [  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 NetBSD
-  AC_MSG_CHECKING([for two-argument statfs with statfs.fsize dnl
+  # 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([[
@@ -223,6 +234,7 @@ 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],
diff --git a/gl/m4/gnulib-comp.m4 b/gl/m4/gnulib-comp.m4
index fc3f3538..b5e6b438 100644
--- a/gl/m4/gnulib-comp.m4
+++ b/gl/m4/gnulib-comp.m4
@@ -254,7 +254,7 @@ AC_DEFUN([gl_INIT],
   # Code from module locale:
   gl_LOCALE_H
   # Code from module malloc:
-  AC_FUNC_MALLOC
+  gl_FUNC_MALLOC_GNU
   AC_DEFINE([GNULIB_MALLOC_GNU], 1, [Define to indicate the 'malloc' module.])
   # Code from module malloc-posix:
   gl_FUNC_MALLOC_POSIX
diff --git a/gl/m4/lib-link.m4 b/gl/m4/lib-link.m4
index 59b367df..9f3be3a2 100644
--- a/gl/m4/lib-link.m4
+++ b/gl/m4/lib-link.m4
@@ -1,4 +1,4 @@
-# lib-link.m4 serial 23 (gettext-0.18.2)
+# lib-link.m4 serial 24 (gettext-0.18.2)
 dnl Copyright (C) 2001-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -165,7 +165,7 @@ AC_DEFUN([AC_LIB_FROMPACKAGE],
   pushdef([PACKUP],[m4_translit(PACK,[abcdefghijklmnopqrstuvwxyz./+-],
                                      [ABCDEFGHIJKLMNOPQRSTUVWXYZ____])])
   define([acl_libsinpackage_]PACKUP,
-    m4_ifdef([acl_libsinpackage_]PACKUP, [acl_libsinpackage_]PACKUP[[, ]],)[lib$1])
+    m4_ifdef([acl_libsinpackage_]PACKUP, [m4_defn([acl_libsinpackage_]PACKUP)[, ]],)[lib$1])
   popdef([PACKUP])
   popdef([PACK])
 ])
diff --git a/gl/m4/malloc.m4 b/gl/m4/malloc.m4
index 910ac922..fe5befc2 100644
--- a/gl/m4/malloc.m4
+++ b/gl/m4/malloc.m4
@@ -1,25 +1,40 @@
-# malloc.m4 serial 9
+# malloc.m4 serial 10
 dnl Copyright (C) 2007, 2009, 2010 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_FUNC_MALLOC_GNU
+# ------------------
+# Test whether 'malloc (0)' is handled like in GNU libc, and replace malloc if
+# it is not.
+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], [1],
+               [Define to 1 if your system has a GNU libc compatible 'malloc'
+                function, and to 0 otherwise.])],
+    [AC_DEFINE([HAVE_MALLOC], [0])
+     gl_REPLACE_MALLOC
+    ])
+])
+
 # gl_FUNC_MALLOC_POSIX
 # --------------------
 # Test whether 'malloc' is POSIX compliant (sets errno to ENOMEM when it
 # fails), and replace malloc if it is not.
 AC_DEFUN([gl_FUNC_MALLOC_POSIX],
 [
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
   AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
   if test $gl_cv_func_malloc_posix = yes; then
-    HAVE_MALLOC_POSIX=1
     AC_DEFINE([HAVE_MALLOC_POSIX], [1],
       [Define if the 'malloc' function is POSIX compliant.])
   else
-    AC_LIBOBJ([malloc])
-    HAVE_MALLOC_POSIX=0
+    gl_REPLACE_MALLOC
   fi
-  AC_SUBST([HAVE_MALLOC_POSIX])
 ])
 
 # Test whether malloc, realloc, calloc are POSIX compliant,
@@ -39,3 +54,9 @@ AC_DEFUN([gl_CHECK_MALLOC_POSIX],
         ], [gl_cv_func_malloc_posix=yes], [gl_cv_func_malloc_posix=no])
     ])
 ])
+
+AC_DEFUN([gl_REPLACE_MALLOC],
+[
+  AC_LIBOBJ([malloc])
+  REPLACE_MALLOC=1
+])
diff --git a/gl/m4/stdlib_h.m4 b/gl/m4/stdlib_h.m4
index dd84796d..fc150197 100644
--- a/gl/m4/stdlib_h.m4
+++ b/gl/m4/stdlib_h.m4
@@ -1,4 +1,4 @@
-# stdlib_h.m4 serial 28
+# stdlib_h.m4 serial 30
 dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -33,7 +33,7 @@ AC_DEFUN([gl_STDLIB_H],
 #if HAVE_RANDOM_H
 # include <random.h>
 #endif
-    ]], [atoll canonicalize_file_name getloadavg getsubopt grantpt mkdtemp
+    ]], [_Exit atoll canonicalize_file_name getloadavg getsubopt grantpt mkdtemp
     mkostemp mkostemps mkstemp mkstemps ptsname random_r initstat_r srandom_r
     setstate_r realpath rpmatch setenv strtod strtoll strtoull unlockpt
     unsetenv])
@@ -50,6 +50,7 @@ AC_DEFUN([gl_STDLIB_MODULE_INDICATOR],
 
 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])
@@ -75,13 +76,12 @@ AC_DEFUN([gl_STDLIB_H_DEFAULTS],
   GNULIB_UNLOCKPT=0;      AC_SUBST([GNULIB_UNLOCKPT])
   GNULIB_UNSETENV=0;      AC_SUBST([GNULIB_UNSETENV])
   dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE__EXIT=1;              AC_SUBST([HAVE__EXIT])
   HAVE_ATOLL=1;              AC_SUBST([HAVE_ATOLL])
-  HAVE_CALLOC_POSIX=1;       AC_SUBST([HAVE_CALLOC_POSIX])
   HAVE_CANONICALIZE_FILE_NAME=1;  AC_SUBST([HAVE_CANONICALIZE_FILE_NAME])
   HAVE_DECL_GETLOADAVG=1;    AC_SUBST([HAVE_DECL_GETLOADAVG])
   HAVE_GETSUBOPT=1;          AC_SUBST([HAVE_GETSUBOPT])
   HAVE_GRANTPT=1;            AC_SUBST([HAVE_GRANTPT])
-  HAVE_MALLOC_POSIX=1;       AC_SUBST([HAVE_MALLOC_POSIX])
   HAVE_MKDTEMP=1;            AC_SUBST([HAVE_MKDTEMP])
   HAVE_MKOSTEMP=1;           AC_SUBST([HAVE_MKOSTEMP])
   HAVE_MKOSTEMPS=1;          AC_SUBST([HAVE_MKOSTEMPS])
@@ -89,7 +89,6 @@ AC_DEFUN([gl_STDLIB_H_DEFAULTS],
   HAVE_MKSTEMPS=1;           AC_SUBST([HAVE_MKSTEMPS])
   HAVE_PTSNAME=1;            AC_SUBST([HAVE_PTSNAME])
   HAVE_RANDOM_R=1;           AC_SUBST([HAVE_RANDOM_R])
-  HAVE_REALLOC_POSIX=1;      AC_SUBST([HAVE_REALLOC_POSIX])
   HAVE_REALPATH=1;           AC_SUBST([HAVE_REALPATH])
   HAVE_RPMATCH=1;            AC_SUBST([HAVE_RPMATCH])
   HAVE_SETENV=1;             AC_SUBST([HAVE_SETENV])
@@ -100,9 +99,12 @@ AC_DEFUN([gl_STDLIB_H_DEFAULTS],
   HAVE_SYS_LOADAVG_H=0;      AC_SUBST([HAVE_SYS_LOADAVG_H])
   HAVE_UNLOCKPT=1;           AC_SUBST([HAVE_UNLOCKPT])
   HAVE_UNSETENV=1;           AC_SUBST([HAVE_UNSETENV])
+  REPLACE_CALLOC=0;          AC_SUBST([REPLACE_CALLOC])
   REPLACE_CANONICALIZE_FILE_NAME=0;  AC_SUBST([REPLACE_CANONICALIZE_FILE_NAME])
+  REPLACE_MALLOC=0;          AC_SUBST([REPLACE_MALLOC])
   REPLACE_MKSTEMP=0;         AC_SUBST([REPLACE_MKSTEMP])
   REPLACE_PUTENV=0;          AC_SUBST([REPLACE_PUTENV])
+  REPLACE_REALLOC=0;         AC_SUBST([REPLACE_REALLOC])
   REPLACE_REALPATH=0;        AC_SUBST([REPLACE_REALPATH])
   REPLACE_SETENV=0;          AC_SUBST([REPLACE_SETENV])
   REPLACE_STRTOD=0;          AC_SUBST([REPLACE_STRTOD])
diff --git a/gl/stdlib.in.h b/gl/stdlib.in.h
index d74c2518..d4ac4690 100644
--- a/gl/stdlib.in.h
+++ b/gl/stdlib.in.h
@@ -74,6 +74,12 @@ struct random_data
 # include <unistd.h>
 #endif
 
+#ifndef __attribute__
+# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8)
+#  define __attribute__(Spec)   /* empty */
+# endif
+#endif
+
 /* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
 
 /* The definition of _GL_ARG_NONNULL is copied here.  */
@@ -95,6 +101,23 @@ struct random_data
 #endif
 
 
+#if @GNULIB__EXIT@
+/* Terminate the current process with the given return code, without running
+   the 'atexit' handlers.  */
+# if !@HAVE__EXIT@
+_GL_FUNCDECL_SYS (_Exit, void, (int status) __attribute__ ((__noreturn__)));
+# endif
+_GL_CXXALIAS_SYS (_Exit, void, (int status));
+_GL_CXXALIASWARN (_Exit);
+#elif defined GNULIB_POSIXCHECK
+# undef _Exit
+# if HAVE_RAW_DECL__EXIT
+_GL_WARN_ON_USE (_Exit, "_Exit is unportable - "
+                 "use gnulib module _Exit for portability");
+# endif
+#endif
+
+
 #if @GNULIB_ATOLL@
 /* Parse a signed decimal integer.
    Returns the value of the integer.  Errors are not detected.  */
@@ -112,7 +135,7 @@ _GL_WARN_ON_USE (atoll, "atoll is unportable - "
 #endif
 
 #if @GNULIB_CALLOC_POSIX@
-# if !@HAVE_CALLOC_POSIX@
+# if @REPLACE_CALLOC@
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
 #   undef calloc
 #   define calloc rpl_calloc
@@ -218,7 +241,7 @@ _GL_WARN_ON_USE (ptsname, "grantpt is not portable - "
 #endif
 
 #if @GNULIB_MALLOC_POSIX@
-# if !@HAVE_MALLOC_POSIX@
+# if @REPLACE_MALLOC@
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
 #   undef malloc
 #   define malloc rpl_malloc
@@ -477,7 +500,7 @@ _GL_WARN_ON_USE (setstate_r, "setstate_r is unportable - "
 
 
 #if @GNULIB_REALLOC_POSIX@
-# if !@HAVE_REALLOC_POSIX@
+# if @REPLACE_REALLOC@
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
 #   undef realloc
 #   define realloc rpl_realloc
diff --git a/gl/str-two-way.h b/gl/str-two-way.h
index c08f60ef..4d555f92 100644
--- a/gl/str-two-way.h
+++ b/gl/str-two-way.h
@@ -95,26 +95,37 @@
    A critical factorization has the property that the local period
    equals the global period.  All strings have at least one critical
    factorization with the left half smaller than the global period.
+   And while some strings have more than one critical factorization,
+   it is provable that with an ordered alphabet, at least one of the
+   critical factorizations corresponds to a maximal suffix.
 
    Given an ordered alphabet, a critical factorization can be computed
    in linear time, with 2 * NEEDLE_LEN comparisons, by computing the
-   larger of two ordered maximal suffixes.  The ordered maximal
-   suffixes are determined by lexicographic comparison of
+   shorter of two ordered maximal suffixes.  The ordered maximal
+   suffixes are determined by lexicographic comparison while tracking
    periodicity.  */
 static size_t
 critical_factorization (const unsigned char *needle, size_t needle_len,
                         size_t *period)
 {
-  /* Index of last byte of left half, or SIZE_MAX.  */
+  /* Index of last byte of left half.  */
   size_t max_suffix, max_suffix_rev;
   size_t j; /* Index into NEEDLE for current candidate suffix.  */
   size_t k; /* Offset into current period.  */
   size_t p; /* Intermediate period.  */
   unsigned char a, b; /* Current comparison bytes.  */
 
+  /* Special case NEEDLE_LEN of 1 or 2 (all callers already filtered
+     out 0-length needles.  */
+  if (needle_len < 3)
+    {
+      *period = 1;
+      return needle_len - 1;
+    }
+
   /* Invariants:
-     0 <= j < NEEDLE_LEN - 1
-     -1 <= max_suffix{,_rev} < j (treating SIZE_MAX as if it were signed)
+     1 <= j < NEEDLE_LEN - 1
+     0 <= max_suffix{,_rev} < j
      min(max_suffix, max_suffix_rev) < global period of NEEDLE
      1 <= p <= global period of NEEDLE
      p == global period of the substring NEEDLE[max_suffix{,_rev}+1...j]
@@ -122,9 +133,8 @@ critical_factorization (const unsigned char *needle, size_t needle_len,
   */
 
   /* Perform lexicographic search.  */
-  max_suffix = SIZE_MAX;
-  j = 0;
-  k = p = 1;
+  max_suffix = 0;
+  j = k = p = 1;
   while (j + k < needle_len)
     {
       a = CANON_ELEMENT (needle[j + k]);
@@ -157,9 +167,8 @@ critical_factorization (const unsigned char *needle, size_t needle_len,
   *period = p;
 
   /* Perform reverse lexicographic search.  */
-  max_suffix_rev = SIZE_MAX;
-  j = 0;
-  k = p = 1;
+  max_suffix_rev = 0;
+  j = k = p = 1;
   while (j + k < needle_len)
     {
       a = CANON_ELEMENT (needle[j + k]);
@@ -190,8 +199,20 @@ critical_factorization (const unsigned char *needle, size_t needle_len,
         }
     }
 
-  /* Choose the longer suffix.  Return the first byte of the right
-     half, rather than the last byte of the left half.  */
+  /* Choose the shorter suffix.  Return the index of the first byte of
+     the right half, rather than the last byte of the left half.
+
+     For some examples, 'banana' has two critical factorizations, both
+     exposed by the two lexicographic extreme suffixes of 'anana' and
+     'nana', where both suffixes have a period of 2.  On the other
+     hand, with 'aab' and 'bba', both strings have a single critical
+     factorization of the last byte, with the suffix having a period
+     of 1.  While the maximal lexicographic suffix of 'aab' is 'b',
+     the maximal lexicographic suffix of 'bba' is 'ba', which is not a
+     critical factorization.  Conversely, the maximal reverse
+     lexicographic suffix of 'a' works for 'bba', but not 'ab' for
+     'aab'.  The shorter suffix of the two will always be a critical
+     factorization.  */
   if (max_suffix_rev + 1 < max_suffix + 1)
     return max_suffix + 1;
   *period = p;
@@ -226,9 +247,9 @@ two_way_short_needle (const unsigned char *haystack, size_t haystack_len,
      first.  */
   if (CMP_FUNC (needle, needle + period, suffix) == 0)
     {
-      /* Entire needle is periodic; a mismatch can only advance by the
-         period, so use memory to avoid rescanning known occurrences
-         of the period.  */
+      /* Entire needle is periodic; a mismatch in the left half can
+         only advance by the period, so use memory to avoid rescanning
+         known occurrences of the period in the right half.  */
       size_t memory = 0;
       j = 0;
       while (AVAILABLE (haystack, haystack_len, j, needle_len))
@@ -330,9 +351,9 @@ two_way_long_needle (const unsigned char *haystack, size_t haystack_len,
      first.  */
   if (CMP_FUNC (needle, needle + period, suffix) == 0)
     {
-      /* Entire needle is periodic; a mismatch can only advance by the
-         period, so use memory to avoid rescanning known occurrences
-         of the period.  */
+      /* Entire needle is periodic; a mismatch in the left half can
+         only advance by the period, so use memory to avoid rescanning
+         known occurrences of the period in the right half.  */
       size_t memory = 0;
       size_t shift;
       j = 0;
diff --git a/gl/string.in.h b/gl/string.in.h
index 13c0f095..f64fce30 100644
--- a/gl/string.in.h
+++ b/gl/string.in.h
@@ -41,10 +41,12 @@
 # if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 5)
 #  define __attribute__(Spec) /* empty */
 # endif
+#endif
 /* The attribute __pure__ was added in gcc 2.96.  */
-# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 96)
-#  define __pure__ /* empty */
-# endif
+#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 96)
+# define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
+#else
+# define _GL_ATTRIBUTE_PURE /* empty */
 #endif
 
 
@@ -62,13 +64,13 @@
 #   define memchr rpl_memchr
 #  endif
 _GL_FUNCDECL_RPL (memchr, void *, (void const *__s, int __c, size_t __n)
-                                  __attribute__ ((__pure__))
+                                  _GL_ATTRIBUTE_PURE
                                   _GL_ARG_NONNULL ((1)));
 _GL_CXXALIAS_RPL (memchr, void *, (void const *__s, int __c, size_t __n));
 # else
 #  if ! @HAVE_MEMCHR@
 _GL_FUNCDECL_SYS (memchr, void *, (void const *__s, int __c, size_t __n)
-                                  __attribute__ ((__pure__))
+                                  _GL_ATTRIBUTE_PURE
                                   _GL_ARG_NONNULL ((1)));
 #  endif
   /* On some systems, this function is defined as an overloaded function:
@@ -102,7 +104,8 @@ _GL_WARN_ON_USE (memchr, "memchr has platform-specific bugs - "
 _GL_FUNCDECL_RPL (memmem, void *,
                   (void const *__haystack, size_t __haystack_len,
                    void const *__needle, size_t __needle_len)
-                  __attribute__ ((__pure__)) _GL_ARG_NONNULL ((1, 3)));
+                  _GL_ATTRIBUTE_PURE
+                  _GL_ARG_NONNULL ((1, 3)));
 _GL_CXXALIAS_RPL (memmem, void *,
                   (void const *__haystack, size_t __haystack_len,
                    void const *__needle, size_t __needle_len));
@@ -111,7 +114,8 @@ _GL_CXXALIAS_RPL (memmem, void *,
 _GL_FUNCDECL_SYS (memmem, void *,
                   (void const *__haystack, size_t __haystack_len,
                    void const *__needle, size_t __needle_len)
-                  __attribute__ ((__pure__)) _GL_ARG_NONNULL ((1, 3)));
+                  _GL_ATTRIBUTE_PURE
+                  _GL_ARG_NONNULL ((1, 3)));
 #  endif
 _GL_CXXALIAS_SYS (memmem, void *,
                   (void const *__haystack, size_t __haystack_len,
@@ -152,7 +156,7 @@ _GL_WARN_ON_USE (mempcpy, "mempcpy is unportable - "
 #if @GNULIB_MEMRCHR@
 # if ! @HAVE_DECL_MEMRCHR@
 _GL_FUNCDECL_SYS (memrchr, void *, (void const *, int, size_t)
-                                   __attribute__ ((__pure__))
+                                   _GL_ATTRIBUTE_PURE
                                    _GL_ARG_NONNULL ((1)));
 # endif
   /* On some systems, this function is defined as an overloaded function:
@@ -182,7 +186,7 @@ _GL_WARN_ON_USE (memrchr, "memrchr is unportable - "
 #if @GNULIB_RAWMEMCHR@
 # if ! @HAVE_RAWMEMCHR@
 _GL_FUNCDECL_SYS (rawmemchr, void *, (void const *__s, int __c_in)
-                                     __attribute__ ((__pure__))
+                                     _GL_ATTRIBUTE_PURE
                                      _GL_ARG_NONNULL ((1)));
 # endif
   /* On some systems, this function is defined as an overloaded function:
@@ -272,7 +276,7 @@ _GL_WARN_ON_USE (strchr, "strchr cannot work correctly on character strings "
 #if @GNULIB_STRCHRNUL@
 # if ! @HAVE_STRCHRNUL@
 _GL_FUNCDECL_SYS (strchrnul, char *, (char const *__s, int __c_in)
-                                     __attribute__ ((__pure__))
+                                     _GL_ATTRIBUTE_PURE
                                      _GL_ARG_NONNULL ((1)));
 # endif
   /* On some systems, this function is defined as an overloaded function:
@@ -378,13 +382,13 @@ _GL_WARN_ON_USE (strndup, "strndup is unportable - "
 #   define strnlen rpl_strnlen
 #  endif
 _GL_FUNCDECL_RPL (strnlen, size_t, (char const *__string, size_t __maxlen)
-                                   __attribute__ ((__pure__))
+                                   _GL_ATTRIBUTE_PURE
                                    _GL_ARG_NONNULL ((1)));
 _GL_CXXALIAS_RPL (strnlen, size_t, (char const *__string, size_t __maxlen));
 # else
 #  if ! @HAVE_DECL_STRNLEN@
 _GL_FUNCDECL_SYS (strnlen, size_t, (char const *__string, size_t __maxlen)
-                                   __attribute__ ((__pure__))
+                                   _GL_ATTRIBUTE_PURE
                                    _GL_ARG_NONNULL ((1)));
 #  endif
 _GL_CXXALIAS_SYS (strnlen, size_t, (char const *__string, size_t __maxlen));
@@ -414,7 +418,7 @@ _GL_WARN_ON_USE (strcspn, "strcspn cannot work correctly on character strings "
 #if @GNULIB_STRPBRK@
 # if ! @HAVE_STRPBRK@
 _GL_FUNCDECL_SYS (strpbrk, char *, (char const *__s, char const *__accept)
-                                   __attribute__ ((__pure__))
+                                   _GL_ATTRIBUTE_PURE
                                    _GL_ARG_NONNULL ((1, 2)));
 # endif
   /* On some systems, this function is defined as an overloaded function:
@@ -514,7 +518,7 @@ _GL_WARN_ON_USE (strsep, "strsep is unportable - "
 #   define strstr rpl_strstr
 #  endif
 _GL_FUNCDECL_RPL (strstr, char *, (const char *haystack, const char *needle)
-                                  __attribute__ ((__pure__))
+                                  _GL_ATTRIBUTE_PURE
                                   _GL_ARG_NONNULL ((1, 2)));
 _GL_CXXALIAS_RPL (strstr, char *, (const char *haystack, const char *needle));
 # else
@@ -556,14 +560,16 @@ _GL_WARN_ON_USE (strstr, "strstr is quadratic on many systems, and cannot "
 #  endif
 _GL_FUNCDECL_RPL (strcasestr, char *,
                   (const char *haystack, const char *needle)
-                  __attribute__ ((__pure__)) _GL_ARG_NONNULL ((1, 2)));
+                  _GL_ATTRIBUTE_PURE
+                  _GL_ARG_NONNULL ((1, 2)));
 _GL_CXXALIAS_RPL (strcasestr, char *,
                   (const char *haystack, const char *needle));
 # else
 #  if ! @HAVE_STRCASESTR@
 _GL_FUNCDECL_SYS (strcasestr, char *,
                   (const char *haystack, const char *needle)
-                  __attribute__ ((__pure__)) _GL_ARG_NONNULL ((1, 2)));
+                  _GL_ATTRIBUTE_PURE
+                  _GL_ARG_NONNULL ((1, 2)));
 #  endif
   /* On some systems, this function is defined as an overloaded function:
        extern "C++" { const char * strcasestr (const char *, const char *); }