GCC: Check if AR works with --plugin and rc

AR from older binutils doesn't work with --plugin and rc:

[hjl@gnu-cfl-2 bin]$ touch foo.c
[hjl@gnu-cfl-2 bin]$ ar --plugin /usr/libexec/gcc/x86_64-redhat-linux/10/liblto_plugin.so rc libfoo.a foo.c
[hjl@gnu-cfl-2 bin]$ ./ar --plugin /usr/libexec/gcc/x86_64-redhat-linux/10/liblto_plugin.so rc libfoo.a foo.c
./ar: no operation specified
[hjl@gnu-cfl-2 bin]$ ./ar --version
GNU ar (Linux/GNU Binutils) 2.29.51.0.1.20180112
Copyright (C) 2018 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or (at your option) any later version.
This program has absolutely no warranty.
[hjl@gnu-cfl-2 bin]$

Check if AR works with --plugin and rc before passing --plugin to AR and
RANLIB.

	PR ld/27173
	* configure: Regenerated.
	* libtool.m4 (_LT_CMD_OLD_ARCHIVE): Check if AR works with
	--plugin and rc before enabling --plugin.

config/

	PR ld/27173
	* gcc-plugin.m4 (GCC_PLUGIN_OPTION): Check if AR works with
	--plugin and rc before enabling --plugin.

libiberty/

	PR ld/27173
	* configure: Regenerated.

zlib/

	PR ld/27173
	* configure: Regenerated.

1 files changed, 8 insertions, 1 deletions

diff --git a/libtool.m4 b/libtool.m4
index 3672e95..9a13f3b 100644
--- a/libtool.m4
+++ b/libtool.m4
@@ -1340,7 +1340,14 @@ AC_CHECK_TOOL(AR, ar, false)
 test -z "$AR" && AR=ar
 if test -n "$plugin_option"; then
   if $AR --help 2>&1 | grep -q "\--plugin"; then
-    AR="$AR $plugin_option"
+    touch conftest.c
+    $AR $plugin_option rc conftest.a conftest.c
+    if test "$?" != 0; then
+      AC_MSG_WARN([Failed: $AR $plugin_option rc])
+    else
+      AR="$AR $plugin_option"
+    fi
+    rm -f conftest.*
   fi
 fi
 test -z "$AR_FLAGS" && AR_FLAGS=cru