[gcc r16-9547] libstdc++: Fix grep for linker warning about --gc-sections [PR126452]

[Jonathan Wakely]

https://gcc.gnu.org/g:7f84e9af923261f3fdd7f15b064c449b7d4157b9

commit r16-9547-g7f84e9af923261f3fdd7f15b064c449b7d4157b9
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Jul 29 16:55:39 2026 +0100

    libstdc++: Fix grep for linker warning about --gc-sections [PR126452]
    
    Current versions of GNU ld print "warning" with a lowercase 'w' so
    adjust the grep patter. Also use LC_ALL=C to ensure the warning isn't
    translated.
    
    Because m4 uses square brackets as quotes, we need to use double
    brackets in the grep pattern to expand to "[Ww]" in the configure
    script.
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/126452
            * acinclude.m4 (GLIBCXX_CHECK_LINKER_FEATURES): Use LC_ALL_C and
            match both "Warning" and "warning" in ld output.
            * configure: Regenerate.
    
    Reviewed-by: Jakub Jelinek <jakub@redhat.com>
    (cherry picked from commit b7ce998a967639b955159eeeae940cb069c518d8)

Diff:
---
 libstdc++-v3/acinclude.m4 |  4 ++--
 libstdc++-v3/configure    | 36 ++++++++++++++++++------------------
 2 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index a615692e7beb..e8c913d9cb59 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -261,8 +261,8 @@ AC_DEFUN([GLIBCXX_CHECK_LINKER_FEATURES], [
       rm -f conftest.c
       touch conftest.c
       if $CC -c conftest.c; then
-	if $LD --gc-sections -o conftest conftest.o 2>&1 | \
-	   grep "Warning: gc-sections option ignored" > /dev/null; then
+	if LC_ALL=C $LD --gc-sections -o conftest conftest.o 2>&1 | \
+	   grep "[[Ww]]arning: gc-sections option ignored" > /dev/null; then
 	  ac_gcsections=no
 	fi
       fi
diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index bc9dce5e2880..5a8d4ae09921 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -23198,8 +23198,8 @@ rm -f core conftest.err conftest.$ac_objext \
       rm -f conftest.c
       touch conftest.c
       if $CC -c conftest.c; then
-	if $LD --gc-sections -o conftest conftest.o 2>&1 | \
-	   grep "Warning: gc-sections option ignored" > /dev/null; then
+	if LC_ALL=C $LD --gc-sections -o conftest conftest.o 2>&1 | \
+	   grep "[Ww]arning: gc-sections option ignored" > /dev/null; then
 	  ac_gcsections=no
 	fi
       fi
@@ -29199,8 +29199,8 @@ rm -f core conftest.err conftest.$ac_objext \
       rm -f conftest.c
       touch conftest.c
       if $CC -c conftest.c; then
-	if $LD --gc-sections -o conftest conftest.o 2>&1 | \
-	   grep "Warning: gc-sections option ignored" > /dev/null; then
+	if LC_ALL=C $LD --gc-sections -o conftest conftest.o 2>&1 | \
+	   grep "[Ww]arning: gc-sections option ignored" > /dev/null; then
 	  ac_gcsections=no
 	fi
       fi
@@ -32381,8 +32381,8 @@ rm -f core conftest.err conftest.$ac_objext \
       rm -f conftest.c
       touch conftest.c
       if $CC -c conftest.c; then
-	if $LD --gc-sections -o conftest conftest.o 2>&1 | \
-	   grep "Warning: gc-sections option ignored" > /dev/null; then
+	if LC_ALL=C $LD --gc-sections -o conftest conftest.o 2>&1 | \
+	   grep "[Ww]arning: gc-sections option ignored" > /dev/null; then
 	  ac_gcsections=no
 	fi
       fi
@@ -38602,8 +38602,8 @@ rm -f core conftest.err conftest.$ac_objext \
       rm -f conftest.c
       touch conftest.c
       if $CC -c conftest.c; then
-	if $LD --gc-sections -o conftest conftest.o 2>&1 | \
-	   grep "Warning: gc-sections option ignored" > /dev/null; then
+	if LC_ALL=C $LD --gc-sections -o conftest conftest.o 2>&1 | \
+	   grep "[Ww]arning: gc-sections option ignored" > /dev/null; then
 	  ac_gcsections=no
 	fi
       fi
@@ -38893,8 +38893,8 @@ rm -f core conftest.err conftest.$ac_objext \
       rm -f conftest.c
       touch conftest.c
       if $CC -c conftest.c; then
-	if $LD --gc-sections -o conftest conftest.o 2>&1 | \
-	   grep "Warning: gc-sections option ignored" > /dev/null; then
+	if LC_ALL=C $LD --gc-sections -o conftest conftest.o 2>&1 | \
+	   grep "[Ww]arning: gc-sections option ignored" > /dev/null; then
 	  ac_gcsections=no
 	fi
       fi
@@ -39361,8 +39361,8 @@ rm -f core conftest.err conftest.$ac_objext \
       rm -f conftest.c
       touch conftest.c
       if $CC -c conftest.c; then
-	if $LD --gc-sections -o conftest conftest.o 2>&1 | \
-	   grep "Warning: gc-sections option ignored" > /dev/null; then
+	if LC_ALL=C $LD --gc-sections -o conftest conftest.o 2>&1 | \
+	   grep "[Ww]arning: gc-sections option ignored" > /dev/null; then
 	  ac_gcsections=no
 	fi
       fi
@@ -42806,8 +42806,8 @@ rm -f core conftest.err conftest.$ac_objext \
       rm -f conftest.c
       touch conftest.c
       if $CC -c conftest.c; then
-	if $LD --gc-sections -o conftest conftest.o 2>&1 | \
-	   grep "Warning: gc-sections option ignored" > /dev/null; then
+	if LC_ALL=C $LD --gc-sections -o conftest conftest.o 2>&1 | \
+	   grep "[Ww]arning: gc-sections option ignored" > /dev/null; then
 	  ac_gcsections=no
 	fi
       fi
@@ -46204,8 +46204,8 @@ rm -f core conftest.err conftest.$ac_objext \
       rm -f conftest.c
       touch conftest.c
       if $CC -c conftest.c; then
-	if $LD --gc-sections -o conftest conftest.o 2>&1 | \
-	   grep "Warning: gc-sections option ignored" > /dev/null; then
+	if LC_ALL=C $LD --gc-sections -o conftest conftest.o 2>&1 | \
+	   grep "[Ww]arning: gc-sections option ignored" > /dev/null; then
 	  ac_gcsections=no
 	fi
       fi
@@ -46420,8 +46420,8 @@ rm -f core conftest.err conftest.$ac_objext \
       rm -f conftest.c
       touch conftest.c
       if $CC -c conftest.c; then
-	if $LD --gc-sections -o conftest conftest.o 2>&1 | \
-	   grep "Warning: gc-sections option ignored" > /dev/null; then
+	if LC_ALL=C $LD --gc-sections -o conftest conftest.o 2>&1 | \
+	   grep "[Ww]arning: gc-sections option ignored" > /dev/null; then
 	  ac_gcsections=no
 	fi
       fi