Track CVS Autoconf on AC_USE_SYSTEM_EXTENSIONS.

* m4/extensions.m4 (AC_USE_SYSTEM_EXTENSIONS): Update to CVS
Autoconf definition.
* modules/euidaccess (Depends-on): Add extensions, for
AC_USE_SYSTEM_EXTENSIONS with autoconf <= 2.59.
* modules/fnmatch (Depends-on): Likewise.
* modules/getaddrinfo (Depends-on): Likewise.
* modules/getdelim (Depends-on): Likewise.
* modules/getline (Depends-on): Likewise.
* modules/getsubopt (Depends-on): Likewise.
* modules/gettext (Depends-on): Likewise.
* modules/group-member (Depends-on): Likewise.
* modules/mbchar (Depends-on): Likewise.
* modules/memmem (Depends-on): Likewise.
* modules/mempcpy (Depends-on): Likewise.
* modules/memrchr (Depends-on): Likewise.
* modules/pagealign_alloc (Depends-on): Likewise.
* modules/readutmp (Depends-on): Likewise.
* modules/stpcpy (Depends-on): Likewise.
* modules/stpncpy (Depends-on): Likewise.
* modules/strchrnul (Depends-on): Likewise.
* modules/strndup (Depends-on): Likewise.
* modules/strsep (Depends-on): Likewise.
* modules/strverscmp (Depends-on): Likewise.
* modules/vasprintf (Depends-on): Likewise.
* modules/wcwidth (Depends-on): Likewise.
* m4/euidaccess.m4 (gl_FUNC_EUIDACCESS): AC_GNU_SOURCE will be
obsolete in Autoconf 2.62; use AC_USE_SYSTEM_EXTENSIONS instead.
* m4/fnmatch.m4 (gl_FUNC_FNMATCH_GNU): Likewise.
* m4/getaddrinfo.m4 (gl_PREREQ_GETADDR_INFO): Likewise.
* m4/getdelim.m4 (gl_FUNC_GETDELIM): Likewise.
* m4/getline.m4 (gl_FUNC_GETLINE): Likewise.
* m4/getsubopt.m4 (gl_FUNC_GETSUBOPT): Likewise.
* m4/glob.m4 (gl_PREREQ_GLOB): Likewise.
* m4/group-member.m4 (gl_FUNC_GROUP_MEMBER): Likewise.
* m4/mbchar.m4 (gl_MBCHAR): Likewise.
* m4/memmem.m4 (gl_FUNC_MEMMEM): Likewise.
* m4/mempcpy.m4 (gl_FUNC_MEMPCPY): Likewise.
* m4/memrchr.m4 (gl_FUNC_MEMRCHR): Likewise.
* m4/mmap-anon.m4 (gl_FUNC_MMAP_ANON): Likewise.
* m4/pagealign_alloc.m4 (gl_PAGEALIGN_ALLOC): Likewise.
* m4/readutmp.m4 (gl_READUTMP): Likewise.
* m4/regex.m4 (gl_PREREQ_REGEX): Likewise.
* m4/stpcpy.m4 (gl_FUNC_STPCPY): Likewise.
* m4/stpncpy.m4 (gl_FUNC_STPNCPY): Likewise.
* m4/strchrnul.m4 (gl_FUNC_STRCHRNUL): Likewise.
* m4/strndup.m4 (gl_FUNC_STRNDUP): Likewise.
* m4/strnlen.m4 (gl_FUNC_STRNLEN): Likewise.
* m4/strsep.m4 (gl_FUNC_STRSEP): Likewise.
* m4/strverscmp.m4 (gl_FUNC_STRVERSCMP): Likewise.
* m4/vasprintf.m4 (gl_PREREQ_VASPRINTF_H): Likewise.
* m4/wcwidth.m4 (gl_FUNC_WCWIDTH): Likewise.
* m4/lock.m4 (gl_LOCK_EARLY_BODY): Likewise, but provide fallback,
so that lock.m4 can be used in gettext without extensions module.

50 files changed, 185 insertions, 74 deletions

diff --git a/ChangeLog b/ChangeLog
index 23ecef924b..f662535ded 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,60 @@
+2007-09-12  Eric Blake  <ebb9@byu.net>
+
+	Track CVS Autoconf on AC_USE_SYSTEM_EXTENSIONS.
+	* m4/extensions.m4 (AC_USE_SYSTEM_EXTENSIONS): Update to CVS
+	Autoconf definition.
+	* modules/euidaccess (Depends-on): Add extensions, for
+	AC_USE_SYSTEM_EXTENSIONS with autoconf <= 2.59.
+	* modules/fnmatch (Depends-on): Likewise.
+	* modules/getaddrinfo (Depends-on): Likewise.
+	* modules/getdelim (Depends-on): Likewise.
+	* modules/getline (Depends-on): Likewise.
+	* modules/getsubopt (Depends-on): Likewise.
+	* modules/gettext (Depends-on): Likewise.
+	* modules/group-member (Depends-on): Likewise.
+	* modules/mbchar (Depends-on): Likewise.
+	* modules/memmem (Depends-on): Likewise.
+	* modules/mempcpy (Depends-on): Likewise.
+	* modules/memrchr (Depends-on): Likewise.
+	* modules/pagealign_alloc (Depends-on): Likewise.
+	* modules/readutmp (Depends-on): Likewise.
+	* modules/stpcpy (Depends-on): Likewise.
+	* modules/stpncpy (Depends-on): Likewise.
+	* modules/strchrnul (Depends-on): Likewise.
+	* modules/strndup (Depends-on): Likewise.
+	* modules/strsep (Depends-on): Likewise.
+	* modules/strverscmp (Depends-on): Likewise.
+	* modules/vasprintf (Depends-on): Likewise.
+	* modules/wcwidth (Depends-on): Likewise.
+	* m4/euidaccess.m4 (gl_FUNC_EUIDACCESS): AC_GNU_SOURCE will be
+	obsolete in Autoconf 2.62; use AC_USE_SYSTEM_EXTENSIONS instead.
+	* m4/fnmatch.m4 (gl_FUNC_FNMATCH_GNU): Likewise.
+	* m4/getaddrinfo.m4 (gl_PREREQ_GETADDR_INFO): Likewise.
+	* m4/getdelim.m4 (gl_FUNC_GETDELIM): Likewise.
+	* m4/getline.m4 (gl_FUNC_GETLINE): Likewise.
+	* m4/getsubopt.m4 (gl_FUNC_GETSUBOPT): Likewise.
+	* m4/glob.m4 (gl_PREREQ_GLOB): Likewise.
+	* m4/group-member.m4 (gl_FUNC_GROUP_MEMBER): Likewise.
+	* m4/mbchar.m4 (gl_MBCHAR): Likewise.
+	* m4/memmem.m4 (gl_FUNC_MEMMEM): Likewise.
+	* m4/mempcpy.m4 (gl_FUNC_MEMPCPY): Likewise.
+	* m4/memrchr.m4 (gl_FUNC_MEMRCHR): Likewise.
+	* m4/mmap-anon.m4 (gl_FUNC_MMAP_ANON): Likewise.
+	* m4/pagealign_alloc.m4 (gl_PAGEALIGN_ALLOC): Likewise.
+	* m4/readutmp.m4 (gl_READUTMP): Likewise.
+	* m4/regex.m4 (gl_PREREQ_REGEX): Likewise.
+	* m4/stpcpy.m4 (gl_FUNC_STPCPY): Likewise.
+	* m4/stpncpy.m4 (gl_FUNC_STPNCPY): Likewise.
+	* m4/strchrnul.m4 (gl_FUNC_STRCHRNUL): Likewise.
+	* m4/strndup.m4 (gl_FUNC_STRNDUP): Likewise.
+	* m4/strnlen.m4 (gl_FUNC_STRNLEN): Likewise.
+	* m4/strsep.m4 (gl_FUNC_STRSEP): Likewise.
+	* m4/strverscmp.m4 (gl_FUNC_STRVERSCMP): Likewise.
+	* m4/vasprintf.m4 (gl_PREREQ_VASPRINTF_H): Likewise.
+	* m4/wcwidth.m4 (gl_FUNC_WCWIDTH): Likewise.
+	* m4/lock.m4 (gl_LOCK_EARLY_BODY): Likewise, but provide fallback,
+	so that lock.m4 can be used in gettext without extensions module.
+
 2007-09-11  Bruno Haible  <bruno@clisp.org>
 
 	* m4/isc-posix.m4: Remove file.
diff --git a/m4/euidaccess.m4 b/m4/euidaccess.m4
index 9edb4b34a5..7690a14315 100644
--- a/m4/euidaccess.m4
+++ b/m4/euidaccess.m4
@@ -1,5 +1,5 @@
-# euidaccess.m4 serial 7
-dnl Copyright (C) 2002-2006 Free Software Foundation, Inc.
+# euidaccess.m4 serial 8
+dnl Copyright (C) 2002-2007 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.
@@ -18,7 +18,7 @@ AC_DEFUN([gl_FUNC_NONREENTRANT_EUIDACCESS],
 AC_DEFUN([gl_FUNC_EUIDACCESS],
 [
   dnl Persuade glibc <unistd.h> to declare euidaccess().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   AC_CHECK_DECLS_ONCE([euidaccess])
   AC_REPLACE_FUNCS(euidaccess)
diff --git a/m4/extensions.m4 b/m4/extensions.m4
index 143a9e5403..bcbb3ceee2 100644
--- a/m4/extensions.m4
+++ b/m4/extensions.m4
@@ -1,14 +1,14 @@
-# serial 4  -*- Autoconf -*-
+# serial 5  -*- Autoconf -*-
 # Enable extensions on systems that normally disable them.
 
-# Copyright (C) 2003, 2006 Free Software Foundation, Inc.
+# Copyright (C) 2003, 2006, 2007 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.
 
 # This definition of AC_USE_SYSTEM_EXTENSIONS is stolen from CVS
 # Autoconf.  Perhaps we can remove this once we can assume Autoconf
-# 2.61 or later everywhere, but since CVS Autoconf mutates rapidly
+# 2.62 or later everywhere, but since CVS Autoconf mutates rapidly
 # enough in this area it's likely we'll need to redefine
 # AC_USE_SYSTEM_EXTENSIONS for quite some time.
 
@@ -16,26 +16,48 @@
 # ------------------------
 # 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__).
 AC_DEFUN([AC_USE_SYSTEM_EXTENSIONS],
-[
-  AC_BEFORE([$0], [AC_COMPILE_IFELSE])
-  AC_BEFORE([$0], [AC_RUN_IFELSE])
+[AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl
+AC_BEFORE([$0], [AC_RUN_IFELSE])dnl
 
-  AC_REQUIRE([AC_GNU_SOURCE])
-  AC_REQUIRE([AC_AIX])
-  AC_REQUIRE([AC_MINIX])
+  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.])
+  fi
 
   AH_VERBATIM([__EXTENSIONS__],
-[/* Enable extensions on Solaris.  */
-#ifndef __EXTENSIONS__
-# undef __EXTENSIONS__
+[/* Enable extensions on AIX 3, Interix.  */
+#ifndef _ALL_SOURCE
+# undef _ALL_SOURCE
+#endif
+/* Enable GNU extensions on systems that have them.  */
+#ifndef _GNU_SOURCE
+# undef _GNU_SOURCE
 #endif
+/* Enable threading extensions on Solaris.  */
 #ifndef _POSIX_PTHREAD_SEMANTICS
 # undef _POSIX_PTHREAD_SEMANTICS
 #endif
+/* Enable extensions on HP NonStop.  */
 #ifndef _TANDEM_SOURCE
 # undef _TANDEM_SOURCE
-#endif])
+#endif
+/* Enable general extensions on Solaris.  */
+#ifndef __EXTENSIONS__
+# undef __EXTENSIONS__
+#endif
+])
   AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
     [ac_cv_safe_to_define___extensions__],
     [AC_COMPILE_IFELSE(
@@ -46,9 +68,11 @@ AC_DEFUN([AC_USE_SYSTEM_EXTENSIONS],
        [ac_cv_safe_to_define___extensions__=no])])
   test $ac_cv_safe_to_define___extensions__ = yes &&
     AC_DEFINE([__EXTENSIONS__])
+  AC_DEFINE([_ALL_SOURCE])
+  AC_DEFINE([_GNU_SOURCE])
   AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
   AC_DEFINE([_TANDEM_SOURCE])
-])
+])# AC_USE_SYSTEM_EXTENSIONS
 
 # gl_USE_SYSTEM_EXTENSIONS
 # ------------------------
diff --git a/m4/fnmatch.m4 b/m4/fnmatch.m4
index 34eb3d91c9..495cbf940e 100644
--- a/m4/fnmatch.m4
+++ b/m4/fnmatch.m4
@@ -1,4 +1,4 @@
-# Check for fnmatch.
+# Check for fnmatch - serial 2.
 
 # Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software
 # Foundation, Inc.
@@ -110,7 +110,7 @@ AC_DEFUN([gl_FUNC_FNMATCH_POSIX],
 AC_DEFUN([gl_FUNC_FNMATCH_GNU],
 [
   dnl Persuade glibc <fnmatch.h> to declare FNM_CASEFOLD etc.
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   FNMATCH_H=
   _AC_FUNC_FNMATCH_IF([GNU], [ac_cv_func_fnmatch_gnu],
diff --git a/m4/getaddrinfo.m4 b/m4/getaddrinfo.m4
index 4a1e09f775..7be1e490ae 100644
--- a/m4/getaddrinfo.m4
+++ b/m4/getaddrinfo.m4
@@ -1,4 +1,4 @@
-# getaddrinfo.m4 serial 12
+# getaddrinfo.m4 serial 13
 dnl Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -81,7 +81,7 @@ AC_DEFUN([gl_PREREQ_GETADDRINFO], [
   AC_REQUIRE([gl_SOCKET_FAMILIES])
   AC_REQUIRE([gl_HEADER_SYS_SOCKET])
   AC_REQUIRE([AC_C_INLINE])
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
   AC_CHECK_HEADERS_ONCE(netinet/in.h netdb.h)
   AC_CHECK_DECLS([getaddrinfo, freeaddrinfo, gai_strerror, getnameinfo],,,[
   /* sys/types.h is not needed according to POSIX, but the
diff --git a/m4/getdelim.m4 b/m4/getdelim.m4
index 7f6e3b41f7..d81be22a72 100644
--- a/m4/getdelim.m4
+++ b/m4/getdelim.m4
@@ -1,4 +1,4 @@
-# getdelim.m4 serial 3
+# getdelim.m4 serial 4
 
 dnl Copyright (C) 2005, 2006, 2007 Free Software dnl Foundation, Inc.
 dnl
@@ -13,7 +13,7 @@ AC_DEFUN([gl_FUNC_GETDELIM],
   AC_REQUIRE([gl_STDIO_H_DEFAULTS])
 
   dnl Persuade glibc <stdio.h> to declare getdelim().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   AC_REPLACE_FUNCS([getdelim])
   AC_CHECK_DECLS_ONCE([getdelim])
diff --git a/m4/getline.m4 b/m4/getline.m4
index 11949b71cc..afd77669ad 100644
--- a/m4/getline.m4
+++ b/m4/getline.m4
@@ -1,4 +1,4 @@
-# getline.m4 serial 16
+# getline.m4 serial 17
 
 dnl Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2005, 2006, 2007 Free
 dnl Software Foundation, Inc.
@@ -18,7 +18,7 @@ AC_DEFUN([gl_FUNC_GETLINE],
   AC_REQUIRE([gl_STDIO_H_DEFAULTS])
 
   dnl Persuade glibc <stdio.h> to declare getline().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   AC_CHECK_DECLS_ONCE([getline])
 
diff --git a/m4/getsubopt.m4 b/m4/getsubopt.m4
index a390a939f8..2c52c754d3 100644
--- a/m4/getsubopt.m4
+++ b/m4/getsubopt.m4
@@ -1,4 +1,4 @@
-# getsubopt.m4 serial 3
+# getsubopt.m4 serial 4
 dnl Copyright (C) 2004, 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,7 +7,7 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_GETSUBOPT],
 [
   dnl Persuade glibc <stdlib.h> to declare getsubopt().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
   AC_CHECK_FUNCS_ONCE([getsubopt])
diff --git a/m4/glob.m4 b/m4/glob.m4
index 061acd4818..1b4c97649d 100644
--- a/m4/glob.m4
+++ b/m4/glob.m4
@@ -1,4 +1,4 @@
-# glob.m4 serial 8
+# glob.m4 serial 9
 dnl Copyright (C) 2005-2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -74,7 +74,7 @@ AC_DEFUN([gl_PREREQ_GLOB],
 [
   AC_REQUIRE([gl_CHECK_TYPE_STRUCT_DIRENT_D_TYPE])dnl
   AC_REQUIRE([AC_C_RESTRICT])dnl
-  AC_REQUIRE([AC_GNU_SOURCE])dnl
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])dnl
   AC_CHECK_HEADERS_ONCE([sys/cdefs.h unistd.h])dnl
   if test $ac_cv_header_sys_cdefs_h = yes; then
     HAVE_SYS_CDEFS_H=1
diff --git a/m4/group-member.m4 b/m4/group-member.m4
index 6f2f57e974..56714912ba 100644
--- a/m4/group-member.m4
+++ b/m4/group-member.m4
@@ -1,6 +1,6 @@
-#serial 10
+#serial 11
 
-# Copyright (C) 1999, 2000, 2001, 2003, 2004, 2005, 2006 Free Software
+# Copyright (C) 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007 Free Software
 # Foundation, Inc.
 
 # This file is free software; the Free Software Foundation
@@ -12,7 +12,7 @@ dnl Written by Jim Meyering
 AC_DEFUN([gl_FUNC_GROUP_MEMBER],
 [
   dnl Persuade glibc <unistd.h> to declare group_member().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   dnl Do this replacement check manually because I want the hyphen
   dnl (not the underscore) in the filename.
diff --git a/m4/lock.m4 b/m4/lock.m4
index 0224f2ff87..1bf3abb003 100644
--- a/m4/lock.m4
+++ b/m4/lock.m4
@@ -1,5 +1,5 @@
-# lock.m4 serial 6 (gettext-0.16)
-dnl Copyright (C) 2005-2006 Free Software Foundation, Inc.
+# lock.m4 serial 7 (gettext-0.16)
+dnl Copyright (C) 2005-2007 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.
@@ -35,7 +35,7 @@ AC_DEFUN([gl_LOCK_EARLY_BODY],
   AC_BEFORE([$0], [gl_ARGP])dnl
 
   AC_REQUIRE([AC_CANONICAL_HOST])
-  AC_REQUIRE([AC_GNU_SOURCE]) dnl needed for pthread_rwlock_t on glibc systems
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) dnl needed for pthread_rwlock_t on glibc systems
   dnl Check for multithreading.
   AC_ARG_ENABLE(threads,
 AC_HELP_STRING([--enable-threads={posix|solaris|pth|win32}], [specify multithreading API])
@@ -257,6 +257,14 @@ AC_DEFUN([gl_PREREQ_LOCK], [
   AC_REQUIRE([AC_C_INLINE])
 ])
 
+# AC_USE_SYSTEM_EXTENSIONS was only added in autoconf 2.60, but lock.m4
+# wants to work with autoconf 2.54.  Add a fallback until such time as
+# a newer autoconf is standard, if one is not already provided by gnulib
+# extensions.m4.
+m4_if(m4_version_compare(m4_PACKAGE_VERSION, [2.60]), [-1],
+      [m4_ifndef([AC_USE_SYSTEM_EXTENSIONS],
+                 [AC_DEFUN([AC_USE_SYSTEM_EXTENSIONS], [AC_GNU_SOURCE])])])
+
 dnl Survey of platforms:
 dnl
 dnl Platform          Available   Compiler    Supports   test-lock
diff --git a/m4/mbchar.m4 b/m4/mbchar.m4
index 02f9effe0d..e73e2b4bef 100644
--- a/m4/mbchar.m4
+++ b/m4/mbchar.m4
@@ -1,4 +1,4 @@
-# mbchar.m4 serial 6
+# mbchar.m4 serial 7
 dnl Copyright (C) 2005-2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -9,5 +9,5 @@ dnl From Bruno Haible.
 
 AC_DEFUN([gl_MBCHAR],
 [
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 ])
diff --git a/m4/memmem.m4 b/m4/memmem.m4
index e6d40068e4..e6a3da193c 100644
--- a/m4/memmem.m4
+++ b/m4/memmem.m4
@@ -1,4 +1,4 @@
-# memmem.m4 serial 4
+# memmem.m4 serial 5
 dnl Copyright (C) 2002, 2003, 2004, 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,7 +7,7 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_MEMMEM],
 [
   dnl Persuade glibc <string.h> to declare memmem().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
   AC_REPLACE_FUNCS(memmem)
diff --git a/m4/mempcpy.m4 b/m4/mempcpy.m4
index 9e854e81ee..13293b5569 100644
--- a/m4/mempcpy.m4
+++ b/m4/mempcpy.m4
@@ -1,4 +1,4 @@
-# mempcpy.m4 serial 7
+# mempcpy.m4 serial 8
 dnl Copyright (C) 2003, 2004, 2006, 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,7 +7,7 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_MEMPCPY],
 [
   dnl Persuade glibc <string.h> to declare mempcpy().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   dnl The mempcpy() declaration in lib/string_.h uses 'restrict'.
   AC_REQUIRE([AC_C_RESTRICT])
diff --git a/m4/memrchr.m4 b/m4/memrchr.m4
index 69674ff418..8070d5fece 100644
--- a/m4/memrchr.m4
+++ b/m4/memrchr.m4
@@ -1,4 +1,4 @@
-# memrchr.m4 serial 7
+# memrchr.m4 serial 8
 dnl Copyright (C) 2002, 2003, 2005, 2006, 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,7 +7,7 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_MEMRCHR],
 [
   dnl Persuade glibc <string.h> to declare memrchr().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
   AC_CHECK_DECLS_ONCE([memrchr])
diff --git a/m4/mmap-anon.m4 b/m4/mmap-anon.m4
index fd8a5370b3..13fbd3c491 100644
--- a/m4/mmap-anon.m4
+++ b/m4/mmap-anon.m4
@@ -1,5 +1,5 @@
-# mmap-anon.m4 serial 3
-dnl Copyright (C) 2005 Free Software Foundation, Inc.
+# mmap-anon.m4 serial 4
+dnl Copyright (C) 2005, 2007 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.
@@ -11,7 +11,7 @@ AC_DEFUN([gl_FUNC_MMAP_ANON],
   AC_REQUIRE([AC_PROG_EGREP])
 
   dnl Persuade glibc <sys/mman.h> to define MAP_ANONYMOUS.
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   # Check for mmap()
   AC_FUNC_MMAP
diff --git a/m4/pagealign_alloc.m4 b/m4/pagealign_alloc.m4
index 6fafef2099..8c53d9d8a0 100644
--- a/m4/pagealign_alloc.m4
+++ b/m4/pagealign_alloc.m4
@@ -1,5 +1,5 @@
-#serial 3
-dnl Copyright (C) 2005, 2006 Free Software Foundation, Inc.
+#serial 4
+dnl Copyright (C) 2005, 2006, 2007 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.
 AC_DEFUN([gl_PAGEALIGN_ALLOC],
 [
   dnl Persuade glibc <sys/mman.h> to define MAP_ANONYMOUS.
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   AC_LIBOBJ([pagealign_alloc])
   gl_PREREQ_PAGEALIGN_ALLOC
diff --git a/m4/readutmp.m4 b/m4/readutmp.m4
index 2e520cd70c..eb6369f4f1 100644
--- a/m4/readutmp.m4
+++ b/m4/readutmp.m4
@@ -1,4 +1,4 @@
-# readutmp.m4 serial 13
+# readutmp.m4 serial 14
 dnl Copyright (C) 2002-2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,7 +7,7 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_READUTMP],
 [
   dnl Persuade utmpx.h to declare utmpxname
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   AC_CHECK_HEADERS_ONCE(utmp.h utmpx.h)
   if test $ac_cv_header_utmp_h = yes || test $ac_cv_header_utmpx_h = yes; then
diff --git a/m4/regex.m4 b/m4/regex.m4
index bde74ea5e7..7da6efedd1 100644
--- a/m4/regex.m4
+++ b/m4/regex.m4
@@ -1,4 +1,4 @@
-#serial 47
+#serial 48
 
 # Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005,
 # 2006, 2007 Free Software Foundation, Inc.
@@ -215,7 +215,7 @@ AC_DEFUN([gl_REGEX],
 # Prerequisites of lib/regex.c and lib/regex_internal.c.
 AC_DEFUN([gl_PREREQ_REGEX],
 [
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
   AC_REQUIRE([AC_C_RESTRICT])
   AC_CHECK_FUNCS_ONCE([isblank iswctype mbrtowc wcrtomb wcscoll])
   AC_CHECK_DECLS([isblank], [], [], [#include <ctype.h>])
diff --git a/m4/stpcpy.m4 b/m4/stpcpy.m4
index c48aa9c3a8..bef09ed060 100644
--- a/m4/stpcpy.m4
+++ b/m4/stpcpy.m4
@@ -1,4 +1,4 @@
-# stpcpy.m4 serial 4
+# stpcpy.m4 serial 5
 dnl Copyright (C) 2002, 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,7 +7,7 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_STPCPY],
 [
   dnl Persuade glibc <string.h> to declare stpcpy().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   dnl The stpcpy() declaration in lib/string_.h uses 'restrict'.
   AC_REQUIRE([AC_C_RESTRICT])
diff --git a/m4/stpncpy.m4 b/m4/stpncpy.m4
index aad0375504..21771321b7 100644
--- a/m4/stpncpy.m4
+++ b/m4/stpncpy.m4
@@ -1,4 +1,4 @@
-# stpncpy.m4 serial 7
+# stpncpy.m4 serial 8
 dnl Copyright (C) 2002-2003, 2005-2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,7 +7,7 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_STPNCPY],
 [
   dnl Persuade glibc <string.h> to declare stpncpy().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   dnl The stpncpy() declaration in lib/string_.h uses 'restrict'.
   AC_REQUIRE([AC_C_RESTRICT])
diff --git a/m4/strchrnul.m4 b/m4/strchrnul.m4
index fec2a10d96..7c1273aa8c 100644
--- a/m4/strchrnul.m4
+++ b/m4/strchrnul.m4
@@ -1,4 +1,4 @@
-# strchrnul.m4 serial 5
+# strchrnul.m4 serial 6
 dnl Copyright (C) 2003, 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,7 +7,7 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_STRCHRNUL],
 [
   dnl Persuade glibc <string.h> to declare strchrnul().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
   AC_REPLACE_FUNCS(strchrnul)
diff --git a/m4/strndup.m4 b/m4/strndup.m4
index baa6c03b8c..f7934ef820 100644
--- a/m4/strndup.m4
+++ b/m4/strndup.m4
@@ -1,4 +1,4 @@
-# strndup.m4 serial 13
+# strndup.m4 serial 14
 dnl Copyright (C) 2002-2003, 2005-2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,7 +7,7 @@ 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_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
   AC_CHECK_DECLS_ONCE([strndup])
@@ -19,7 +19,7 @@ AC_DEFUN([gl_FUNC_STRNDUP],
   AC_CACHE_CHECK([for working strndup], gl_cv_func_strndup,
     [AC_RUN_IFELSE([
        AC_LANG_PROGRAM([#include <string.h>
-		 	#include <stdlib.h>], [[
+			#include <stdlib.h>], [[
 #ifndef HAVE_DECL_STRNDUP
   extern char *strndup (const char *, size_t);
 #endif
diff --git a/m4/strnlen.m4 b/m4/strnlen.m4
index 0e2815b90e..d8307eda4a 100644
--- a/m4/strnlen.m4
+++ b/m4/strnlen.m4
@@ -1,4 +1,4 @@
-# strnlen.m4 serial 8
+# strnlen.m4 serial 9
 dnl Copyright (C) 2002-2003, 2005-2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,7 +7,7 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_STRNLEN],
 [
   dnl Persuade glibc <string.h> to declare strnlen().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
   AC_CHECK_DECLS_ONCE([strnlen])
@@ -17,7 +17,7 @@ AC_DEFUN([gl_FUNC_STRNLEN],
 
   AC_FUNC_STRNLEN
   if test $ac_cv_func_strnlen_working = no; then
-    # This is necessary because automake-1.6.1 doens't understand
+    # This is necessary because automake-1.6.1 doesn't understand
     # that the above use of AC_FUNC_STRNLEN means we may have to use
     # lib/strnlen.c.
     #AC_LIBOBJ(strnlen)
diff --git a/m4/strsep.m4 b/m4/strsep.m4
index 0abbf089ce..acbd8d1c00 100644
--- a/m4/strsep.m4
+++ b/m4/strsep.m4
@@ -1,4 +1,4 @@
-# strsep.m4 serial 6
+# strsep.m4 serial 7
 dnl Copyright (C) 2002, 2003, 2004, 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,7 +7,7 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_STRSEP],
 [
   dnl Persuade glibc <string.h> to declare strsep().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   dnl The strsep() declaration in lib/string_.h uses 'restrict'.
   AC_REQUIRE([AC_C_RESTRICT])
diff --git a/m4/strverscmp.m4 b/m4/strverscmp.m4
index ab20c1809d..5f01ba9e5b 100644
--- a/m4/strverscmp.m4
+++ b/m4/strverscmp.m4
@@ -1,5 +1,5 @@
-# strverscmp.m4 serial 4
-dnl Copyright (C) 2002, 2005, 2006 Free Software Foundation, Inc.
+# strverscmp.m4 serial 5
+dnl Copyright (C) 2002, 2005, 2006, 2007 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.
 AC_DEFUN([gl_FUNC_STRVERSCMP],
 [
   dnl Persuade glibc <string.h> to declare strverscmp().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   AC_REPLACE_FUNCS(strverscmp)
   if test $ac_cv_func_strverscmp = no; then
diff --git a/m4/vasprintf.m4 b/m4/vasprintf.m4
index 4f0c79a71a..074b03cf72 100644
--- a/m4/vasprintf.m4
+++ b/m4/vasprintf.m4
@@ -1,4 +1,4 @@
-# vasprintf.m4 serial 5
+# vasprintf.m4 serial 6
 dnl Copyright (C) 2002-2003, 2006-2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -31,7 +31,7 @@ AC_DEFUN([gl_REPLACE_VASPRINTF],
 AC_DEFUN([gl_PREREQ_VASPRINTF_H],
 [
   dnl Persuade glibc <stdio.h> to declare asprintf() and vasprintf().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 ])
 
 # Prerequisites of lib/vasprintf.c.
diff --git a/m4/wcwidth.m4 b/m4/wcwidth.m4
index a260998a8b..df7919bd73 100644
--- a/m4/wcwidth.m4
+++ b/m4/wcwidth.m4
@@ -1,4 +1,4 @@
-# wcwidth.m4 serial 11
+# wcwidth.m4 serial 12
 dnl Copyright (C) 2006, 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -9,7 +9,7 @@ AC_DEFUN([gl_FUNC_WCWIDTH],
   AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
 
   dnl Persuade glibc <wchar.h> to declare wcwidth().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   AC_REQUIRE([gt_TYPE_WCHAR_T])
   AC_REQUIRE([gt_TYPE_WINT_T])
diff --git a/modules/euidaccess b/modules/euidaccess
index 66cfdd805c..d1bd3e13d4 100644
--- a/modules/euidaccess
+++ b/modules/euidaccess
@@ -7,6 +7,7 @@ lib/euidaccess.c
 m4/euidaccess.m4
 
 Depends-on:
+extensions
 group-member
 sys_stat
 
diff --git a/modules/fnmatch b/modules/fnmatch
index c8abf8936a..79ffc0a84e 100644
--- a/modules/fnmatch
+++ b/modules/fnmatch
@@ -9,6 +9,7 @@ m4/mbstate_t.m4
 m4/fnmatch.m4
 
 Depends-on:
+extensions
 alloca
 stdbool
 wchar
diff --git a/modules/getaddrinfo b/modules/getaddrinfo
index 5d6a3dc895..b9964655ea 100644
--- a/modules/getaddrinfo
+++ b/modules/getaddrinfo
@@ -8,6 +8,7 @@ lib/gai_strerror.c
 m4/getaddrinfo.m4
 
 Depends-on:
+extensions
 gettext-h
 inet_ntop
 snprintf
diff --git a/modules/getdelim b/modules/getdelim
index 19ca193c7f..a9b7b2e388 100644
--- a/modules/getdelim
+++ b/modules/getdelim
@@ -6,6 +6,7 @@ lib/getdelim.c
 m4/getdelim.m4
 
 Depends-on:
+extensions
 stdio
 realloc-posix
 
diff --git a/modules/getline b/modules/getline
index 82901293bd..1fb9b9c22e 100644
--- a/modules/getline
+++ b/modules/getline
@@ -6,6 +6,7 @@ lib/getline.c
 m4/getline.m4
 
 Depends-on:
+extensions
 getdelim
 stdio
 
diff --git a/modules/getsubopt b/modules/getsubopt
index 52e5d9e87e..bf72b06572 100644
--- a/modules/getsubopt
+++ b/modules/getsubopt
@@ -6,6 +6,7 @@ lib/getsubopt.c
 m4/getsubopt.m4
 
 Depends-on:
+extensions
 strchrnul
 stdlib
 
diff --git a/modules/gettext b/modules/gettext
index 4e1e682a06..83833e5756 100644
--- a/modules/gettext
+++ b/modules/gettext
@@ -32,6 +32,7 @@ m4/xsize.m4
 build-aux/config.rpath
 
 Depends-on:
+extensions
 gettext-h
 havelib
 
diff --git a/modules/group-member b/modules/group-member
index 6432a4fdc3..45c8bd5607 100644
--- a/modules/group-member
+++ b/modules/group-member
@@ -7,6 +7,7 @@ lib/group-member.c
 m4/group-member.m4
 
 Depends-on:
+extensions
 xalloc
 stdbool
 
diff --git a/modules/mbchar b/modules/mbchar
index ec3ed27f55..fcda4b77b1 100644
--- a/modules/mbchar
+++ b/modules/mbchar
@@ -7,6 +7,7 @@ lib/mbchar.c
 m4/mbchar.m4
 
 Depends-on:
+extensions
 stdbool
 wchar
 wctype
diff --git a/modules/memmem b/modules/memmem
index 847d527588..c51ee30939 100644
--- a/modules/memmem
+++ b/modules/memmem
@@ -6,6 +6,7 @@ lib/memmem.c
 m4/memmem.m4
 
 Depends-on:
+extensions
 string
 
 configure.ac:
diff --git a/modules/mempcpy b/modules/mempcpy
index ebb4613df8..5fd8bdce87 100644
--- a/modules/mempcpy
+++ b/modules/mempcpy
@@ -6,6 +6,7 @@ lib/mempcpy.c
 m4/mempcpy.m4
 
 Depends-on:
+extensions
 string
 
 configure.ac:
diff --git a/modules/memrchr b/modules/memrchr
index 54912ccb0b..3a6e982b68 100644
--- a/modules/memrchr
+++ b/modules/memrchr
@@ -6,6 +6,7 @@ lib/memrchr.c
 m4/memrchr.m4
 
 Depends-on:
+extensions
 string
 
 configure.ac:
diff --git a/modules/pagealign_alloc b/modules/pagealign_alloc
index 78e6d708cb..1425b41658 100644
--- a/modules/pagealign_alloc
+++ b/modules/pagealign_alloc
@@ -10,6 +10,7 @@ m4/pagealign_alloc.m4
 Depends-on:
 error
 exit
+extensions
 getpagesize
 gettext-h
 xalloc
diff --git a/modules/readutmp b/modules/readutmp
index 8c4f84747d..fd813be89c 100644
--- a/modules/readutmp
+++ b/modules/readutmp
@@ -7,6 +7,7 @@ lib/readutmp.c
 m4/readutmp.m4
 
 Depends-on:
+extensions
 xalloc
 free
 stdbool
diff --git a/modules/stpcpy b/modules/stpcpy
index de70b10292..085397193e 100644
--- a/modules/stpcpy
+++ b/modules/stpcpy
@@ -6,6 +6,7 @@ lib/stpcpy.c
 m4/stpcpy.m4
 
 Depends-on:
+extensions
 string
 
 configure.ac:
diff --git a/modules/stpncpy b/modules/stpncpy
index 6453c80943..48eedf71b1 100644
--- a/modules/stpncpy
+++ b/modules/stpncpy
@@ -6,6 +6,7 @@ lib/stpncpy.c
 m4/stpncpy.m4
 
 Depends-on:
+extensions
 string
 
 configure.ac:
diff --git a/modules/strchrnul b/modules/strchrnul
index d79d63eb02..806aebbe0a 100644
--- a/modules/strchrnul
+++ b/modules/strchrnul
@@ -6,6 +6,7 @@ lib/strchrnul.c
 m4/strchrnul.m4
 
 Depends-on:
+extensions
 string
 
 configure.ac:
diff --git a/modules/strndup b/modules/strndup
index fad66a18d0..80f143bee5 100644
--- a/modules/strndup
+++ b/modules/strndup
@@ -6,6 +6,7 @@ lib/strndup.c
 m4/strndup.m4
 
 Depends-on:
+extensions
 string
 strnlen
 
diff --git a/modules/strsep b/modules/strsep
index 51ae226c7c..10ca817a82 100644
--- a/modules/strsep
+++ b/modules/strsep
@@ -6,6 +6,7 @@ lib/strsep.c
 m4/strsep.m4
 
 Depends-on:
+extensions
 string
 strpbrk
 
diff --git a/modules/strverscmp b/modules/strverscmp
index df634803a4..ad18c1f84a 100644
--- a/modules/strverscmp
+++ b/modules/strverscmp
@@ -7,6 +7,7 @@ lib/strverscmp.c
 m4/strverscmp.m4
 
 Depends-on:
+extensions
 
 configure.ac:
 gl_FUNC_STRVERSCMP
diff --git a/modules/vasprintf b/modules/vasprintf
index e57575e1d8..6ca71bd311 100644
--- a/modules/vasprintf
+++ b/modules/vasprintf
@@ -7,6 +7,7 @@ lib/asprintf.c
 m4/vasprintf.m4
 
 Depends-on:
+extensions
 vasnprintf
 stdio
 
diff --git a/modules/wcwidth b/modules/wcwidth
index 74743947e1..fe410f150f 100644
--- a/modules/wcwidth
+++ b/modules/wcwidth
@@ -8,6 +8,7 @@ m4/wchar_t.m4
 m4/wint_t.m4
 
 Depends-on:
+extensions
 wchar
 wctype
 localcharset