[COMMITTED] config: Sync from GCC

[Pietro Monteiro <pietro@sociotechnical.xyz>]

Sync the following changes from GCC and regenerate all autoconf files.

commit 3d61ec632f9292fb7642865d8b588bb82d51d466
Author: Sam James <sam@gentoo.org>
Date:   Sun Oct 11 20:15:54 2026 +0100

    config: sync ax_check_define.m4 from autoconf-archive

    config/ChangeLog:

    	* ax_check_define.m4: Update to serial 12.

commit 9d3338579f6448dcffa6f0b818c45374f925f3d5
Author: Zhongteng Gui <dragon-archer@outlook.com>
Date:   Sat Oct 10 01:17:17 2026 +0800

    lto, mingw: Do not export symbols from some frontends [PR115300]

    config/ChangeLog:

    	* bootstrap-lto-lean.mk (STAGE3_CFLAGS): Add -ffat-lto-objects for
            mingw targets.
            (STAGEfeedback_CFLAGS): Likewise.

commit c767ce6c57c2a4b60c6c7725ac7e06cb18b9258b
Author: Pietro Monteiro <pietro@sociotechnical.xyz>
Date:   Mon Oct 26 18:22:21 2026 -0400

    config: Update AC_PROG_LD to LT_PATH_LD.

    config/ChangeLog:

    	* hwcaps.m4 (GCC_CHECK_LINKER_HWCAP): Update AC_PROG_LD to LT_PATH_LD.

Signed-off-by: Pietro Monteiro <pietro@sociotechnical.xyz>
---
 config/ax_check_define.m4    | 39 +++++++++---------------------------
 config/bootstrap-lto-lean.mk |  4 ++++
 config/hwcaps.m4             |  2 +-
 3 files changed, 15 insertions(+), 30 deletions(-)

diff --git a/config/ax_check_define.m4 b/config/ax_check_define.m4
index 4bc694861c0..ef15e713005 100644
--- a/config/ax_check_define.m4
+++ b/config/ax_check_define.m4
@@ -1,5 +1,5 @@
 # ===========================================================================
-#      http://www.gnu.org/software/autoconf-archive/ax_check_define.html
+#     https://www.gnu.org/software/autoconf-archive/ax_check_define.html
 # ===========================================================================
 #
 # SYNOPSIS
@@ -18,33 +18,12 @@
 #
 #   Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
 #
-#   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 <http://www.gnu.org/licenses/>.
-#
-#   As a special exception, the respective Autoconf Macro's copyright owner
-#   gives unlimited permission to copy, distribute and modify the configure
-#   scripts that are the output of Autoconf when processing the Macro. You
-#   need not follow the terms of the GNU General Public License when using
-#   or distributing such scripts, even though portions of the text of the
-#   Macro appear in them. The GNU General Public License (GPL) does govern
-#   all other use of the material that constitutes the Autoconf Macro.
-#
-#   This special exception to the GPL applies to versions of the Autoconf
-#   Macro released by the Autoconf Archive. When you make and distribute a
-#   modified version of the Autoconf Macro, you may extend this special
-#   exception to the GPL to apply to your modified version as well.
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved.  This file is offered as-is, without any
+#   warranty.
 
-#serial 8
+#serial 12
 
 AU_ALIAS([AC_CHECK_DEFINED], [AC_CHECK_DEFINE])
 AC_DEFUN([AC_CHECK_DEFINE],[
@@ -53,6 +32,7 @@ AC_CACHE_CHECK([for $1 defined], ac_var,
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[
   #ifdef $1
   int ok;
+  (void)ok;
   #else
   choke me
   #endif
@@ -68,6 +48,7 @@ AC_CACHE_CHECK([for $2 defined in $1], ac_var,
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <$1>]], [[
   #ifdef $2
   int ok;
+  (void)ok;
   #else
   choke me
   #endif
@@ -82,8 +63,8 @@ AC_CACHE_CHECK([for $2], ac_var,
 dnl AC_LANG_FUNC_LINK_TRY
 [AC_LINK_IFELSE([AC_LANG_PROGRAM([$1
                 #undef $2
-                char $2 ();],[
-                char (*f) () = $2;
+                char $2 (void);],[
+                char (*f) (void) = $2;
                 return f != $2; ])],
                 [AS_VAR_SET(ac_var, yes)],
                 [AS_VAR_SET(ac_var, no)])])
diff --git a/config/bootstrap-lto-lean.mk b/config/bootstrap-lto-lean.mk
index 42cb3394c70..5f3d2b56fbf 100644
--- a/config/bootstrap-lto-lean.mk
+++ b/config/bootstrap-lto-lean.mk
@@ -5,6 +5,10 @@ STAGE3_CFLAGS += -flto=jobserver
 override STAGEtrain_CFLAGS := $(filter-out -flto=jobserver,$(STAGEtrain_CFLAGS))
 STAGEtrain_GENERATOR_CFLAGS += -flto=jobserver
 STAGEfeedback_CFLAGS += -flto=jobserver
+ifneq (,$(findstring mingw,$(host_os)))
+STAGE3_CFLAGS += -ffat-lto-objects
+STAGEfeedback_CFLAGS += -ffat-lto-objects
+endif
 
 # assumes the host supports the linker plugin
 LTO_AR = $$r/$(HOST_SUBDIR)/prev-gcc/gcc-ar$(exeext) -B$$r/$(HOST_SUBDIR)/prev-gcc/
diff --git a/config/hwcaps.m4 b/config/hwcaps.m4
index f3d03906447..aedbc4913fb 100644
--- a/config/hwcaps.m4
+++ b/config/hwcaps.m4
@@ -42,7 +42,7 @@ dnl  LD (as a side effect of testing)
 dnl
 AC_DEFUN([GCC_CHECK_LINKER_HWCAP], [
   test -z "$HWCAP_LDFLAGS" && HWCAP_LDFLAGS=''
-  AC_REQUIRE([AC_PROG_LD])
+  AC_REQUIRE([LT_PATH_LD])
 
   ac_save_LDFLAGS="$LDFLAGS"
   LDFLAGS="$LFLAGS -mclear-hwcap"
-- 
2.54.0