[glibc/azanella/clang] Only use -finput-charset=ascii iff compiler supports it

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=6abb12244272cfb37f5f85cbf4693be5405ec564

commit 6abb12244272cfb37f5f85cbf4693be5405ec564
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Fri Mar 25 13:58:03 2022 -0300

    Only use -finput-charset=ascii iff compiler supports it

Diff:
---
 Makefile                           |  2 ++
 Rules                              |  2 ++
 configure                          | 24 ++++++++++++++++++++++++
 configure.ac                       |  9 +++++++++
 scripts/check-installed-headers.sh | 12 +++++++++---
 5 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 7052b46df8..cf7fa7a370 100644
--- a/Makefile
+++ b/Makefile
@@ -546,6 +546,7 @@ libof-check-installed-headers-c := testsuite
 $(objpfx)check-installed-headers-c.out: \
     scripts/check-installed-headers.sh $(headers)
 	$(SHELL) $(..)scripts/check-installed-headers.sh c $(supported-fortify) \
+	  $(config-cflags-charset-ascii) \
 	  "$(CC) $(filter-out -std=%,$(CFLAGS)) -D_ISOMAC $(+includes)" \
 	  $(headers) > $@; \
 	$(evaluate-test)
@@ -556,6 +557,7 @@ libof-check-installed-headers-cxx := testsuite
 $(objpfx)check-installed-headers-cxx.out: \
     scripts/check-installed-headers.sh $(headers)
 	$(SHELL) $(..)scripts/check-installed-headers.sh c++ $(supported-fortify) \
+	  $(config-cflags-charset-ascii) \
 	  "$(CXX) $(filter-out -std=%,$(CXXFLAGS)) -D_ISOMAC $(+includes)" \
 	  $(headers) > $@; \
 	$(evaluate-test)
diff --git a/Rules b/Rules
index c7db0a4869..d90f019629 100644
--- a/Rules
+++ b/Rules
@@ -86,6 +86,7 @@ libof-check-installed-headers-c := testsuite
 $(objpfx)check-installed-headers-c.out: \
     $(..)scripts/check-installed-headers.sh $(headers)
 	$(SHELL) $(..)scripts/check-installed-headers.sh c $(supported-fortify) \
+	  $(config-cflags-charset-ascii) \
 	  "$(CC) $(filter-out -std=%,$(CFLAGS)) -D_ISOMAC $(+includes)" \
 	  $(headers) > $@; \
 	$(evaluate-test)
@@ -98,6 +99,7 @@ libof-check-installed-headers-cxx := testsuite
 $(objpfx)check-installed-headers-cxx.out: \
     $(..)scripts/check-installed-headers.sh $(headers)
 	$(SHELL) $(..)scripts/check-installed-headers.sh c++ $(supported-fortify) \
+	  $(config-cflags-charset-ascii) \
 	  "$(CXX) $(filter-out -std=%,$(CXXFLAGS)) -D_ISOMAC $(+includes)" \
 	  $(headers) > $@; \
 	$(evaluate-test)
diff --git a/configure b/configure
index c148a663f3..296fcb6e0b 100755
--- a/configure
+++ b/configure
@@ -7484,6 +7484,30 @@ printf "%s\n" "$libc_cv_cc_trampoline" >&6; }
 config_vars="$config_vars
 have-cc-trampoline = $libc_cv_cc_trampoline"
 
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if $CC supports -finput-charset=ascii" >&5
+printf %s "checking if $CC supports -finput-charset=ascii... " >&6; }
+if test ${libc_cv_cc_charset_ascii+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  if { ac_try='${CC-cc} -Werror -finput-charset=ascii -xc /dev/null -S -o /dev/null'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then :
+  libc_cv_cc_charset_ascii="yes"
+else $as_nop
+  libc_cv_cc_charset_ascii="no"
+fi
+
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_cc_charset_ascii" >&5
+printf "%s\n" "$libc_cv_cc_charset_ascii" >&6; }
+config_vars="$config_vars
+config-cflags-charset-ascii = $libc_cv_cc_charset_ascii"
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for libgd" >&5
 printf %s "checking for libgd... " >&6; }
 if test "$with_gd" != "no"; then
diff --git a/configure.ac b/configure.ac
index 24fb4adb7b..80bf04627b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1543,6 +1543,15 @@ rm -f conftest*])
 LIBC_CONFIG_VAR([have-cc-trampoline],
 		[$libc_cv_cc_trampoline])
 
+AC_CACHE_CHECK([if $CC supports -finput-charset=ascii],
+	       libc_cv_cc_charset_ascii, [dnl
+LIBC_TRY_CC_OPTION([-Werror -finput-charset=ascii],
+		   [libc_cv_cc_charset_ascii="yes"],
+		   [libc_cv_cc_charset_ascii="no"])
+])
+LIBC_CONFIG_VAR([config-cflags-charset-ascii],
+		[$libc_cv_cc_charset_ascii])
+
 dnl Check whether we have the gd library available.
 AC_MSG_CHECKING(for libgd)
 if test "$with_gd" != "no"; then
diff --git a/scripts/check-installed-headers.sh b/scripts/check-installed-headers.sh
index b8cdcbf858..25a7f2605d 100644
--- a/scripts/check-installed-headers.sh
+++ b/scripts/check-installed-headers.sh
@@ -33,8 +33,8 @@ lib_modes="-D_DEFAULT_SOURCE=1 -D_GNU_SOURCE=1 -D_XOPEN_SOURCE=700"
 # maximum value to be checked is define by maximum_fortify argument.
 fortify_modes=""
 
-if [ $# -lt 3 ]; then
-    echo "usage: $0 c|c++ maximum_fortify \"compile command\" header header header..." >&2
+if [ $# -lt 4 ]; then
+    echo "usage: $0 c|c++ maximum_fortify finput-charset \"compile command\" header header header..." >&2
     exit 2
 fi
 case "$1" in
@@ -53,6 +53,12 @@ esac
 shift
 fortify_modes=$(seq -s' ' 1 $1)
 shift
+if [ "$1" = "yes" ]; then
+  finputcharset="-finput-charset=ascii"
+else
+  finputcharset=""
+fi
+shift
 cc_cmd="$1"
 shift
 trap "rm -f '$cih_test_c'" 0
@@ -130,7 +136,7 @@ $expanded_lib_mode
 #include <$header>
 int avoid_empty_translation_unit;
 EOF
-                if $cc_cmd -finput-charset=ascii -fsyntax-only $lang_mode \
+                if $cc_cmd $finputcharset -fsyntax-only $lang_mode \
 		           "$cih_test_c" 2>&1
                 then :
                 else failed=1