* m4/extensions.m4 (AC_CHECK_INCLUDES_DEFAULT):
Provide a default implementation for Autoconf 2.69 or earlier.
(AC_USE_SYSTEM_EXTENSIONS): Copy from Autoconf git. Define only
if Autoconf 2.70 or earlier, since 2.70.1 or later should be OK.
---
ChangeLog | 6 ++
m4/extensions.m4 | 152 +++++++++++++++++++++++++++++------------------
2 files changed, 99 insertions(+), 59 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index d559fcbaa..e9a72ec11 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2020-12-11 Paul Eggert <egg...@cs.ucla.edu>
+ extensions: update from Autoconf
+ * m4/extensions.m4 (AC_CHECK_INCLUDES_DEFAULT):
+ Provide a default implementation for Autoconf 2.69 or earlier.
+ (AC_USE_SYSTEM_EXTENSIONS): Copy from Autoconf git. Define only
+ if Autoconf 2.70 or earlier, since 2.70.1 or later should be OK.
+
alloca: update from Autoconf
* m4/alloca.m4 (gl_PREREQ_ALLOCA):
Trivial update to match Autoconf 2.70.
diff --git a/m4/extensions.m4 b/m4/extensions.m4
index 31790801e..44be1d15c 100644
--- a/m4/extensions.m4
+++ b/m4/extensions.m4
@@ -1,4 +1,4 @@
-# serial 20 -*- Autoconf -*-
+# serial 21 -*- Autoconf -*-
# Enable extensions on systems that normally disable them.
# Copyright (C) 2003, 2006-2020 Free Software Foundation, Inc.
@@ -6,9 +6,14 @@
# 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.
@@ -26,36 +31,27 @@
# its dependencies. This will ensure that the gl_USE_SYSTEM_EXTENSIONS
# invocation occurs in gl_EARLY, not in gl_INIT.
+m4_version_prereq([2.70.1], [], [
+
# 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
@@ -64,19 +60,44 @@ dnl configure.ac when using autoheader 2.62.
#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 NetBSD extensions on NetBSD. */
+/* 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 extensions on NetBSD. */
+/* Enable OpenBSD compatibility extensions on NetBSD.
+ Oddly enough, this does nothing on OpenBSD. */
#ifndef _OPENBSD_SOURCE
# undef _OPENBSD_SOURCE
#endif
-/* Enable threading extensions on Solaris. */
+/* 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
@@ -112,22 +133,19 @@ dnl configure.ac when using autoheader 2.62.
#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 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
-/* 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(
@@ -136,11 +154,33 @@ 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__])
+
+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
+ 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_LANG_PROGRAM([[
+ #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])
@@ -152,24 +192,18 @@ dnl configure.ac when using autoheader 2.62.
AC_DEFINE([__STDC_WANT_LIB_EXT2__])
AC_DEFINE([__STDC_WANT_MATH_SPEC_FUNCS__])
AC_DEFINE([_TANDEM_SOURCE])
- 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([[
- #include <wchar.h>
- mbstate_t x;]])],
- [],
- [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])
- AC_DEFINE([_HPUX_ALT_XOPEN_SOCKET_API])
+ 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
# ------------------------
--
2.28.0
