[glibc] mach: Fix passing -ffreestanding when checking for gnumach headers

[Samuel Thibault <sthibaul@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=7685630b98ca2a3f5de86eadf130993e6cf998a0

commit 7685630b98ca2a3f5de86eadf130993e6cf998a0
Author: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date:   Mon Dec 19 02:34:55 2022 +0100

    mach: Fix passing -ffreestanding when checking for gnumach headers
    
    8b8c768e3c70 ("Force use of -ffreestanding when checking for gnumach
    headers") was passing -ffreestanding to CFLAGS only, but headers checks are
    performed with the preprocessor, so we rather need to pass it to CPPFLAGS.

Diff:
---
 sysdeps/mach/configure    | 9 +++------
 sysdeps/mach/configure.ac | 9 +++------
 2 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/sysdeps/mach/configure b/sysdeps/mach/configure
index 36f556a663..ba6371cd3f 100644
--- a/sysdeps/mach/configure
+++ b/sysdeps/mach/configure
@@ -127,14 +127,13 @@ fi
 config_vars="$config_vars
 MIG = $MIG"
 
+OLD_CPPFLAGS=$CPPFLAGS
 if test -n "$sysheaders"; then
-  OLD_CPPFLAGS=$CPPFLAGS
   CPPFLAGS="$CPPFLAGS $SYSINCLUDES"
 fi
 
 ### Sanity checks for Mach header installation
-old_CFLAGS=$CFLAGS
-CFLAGS="$CFLAGS -ffreestanding"
+CPPFLAGS="$CPPFLAGS -ffreestanding"
 
 
 ac_fn_c_check_header_preproc "$LINENO" "mach/mach_types.h" "ac_cv_header_mach_mach_types_h"
@@ -527,6 +526,4 @@ if test $hurd_cv_mig_retcode = yes; then
 
 fi
 
-if test -n "$sysheaders"; then
-  CPPFLAGS=$OLD_CPPFLAGS
-fi
+CPPFLAGS=$OLD_CPPFLAGS
diff --git a/sysdeps/mach/configure.ac b/sysdeps/mach/configure.ac
index 5816c3d4ad..900e5445c5 100644
--- a/sysdeps/mach/configure.ac
+++ b/sysdeps/mach/configure.ac
@@ -6,14 +6,13 @@ if test "x$MIG" = xMISSING; then
 fi
 LIBC_CONFIG_VAR([MIG], [$MIG])
 
+OLD_CPPFLAGS=$CPPFLAGS
 if test -n "$sysheaders"; then
-  OLD_CPPFLAGS=$CPPFLAGS
   CPPFLAGS="$CPPFLAGS $SYSINCLUDES"
 fi
 
 ### Sanity checks for Mach header installation
-old_CFLAGS=$CFLAGS
-CFLAGS="$CFLAGS -ffreestanding"
+CPPFLAGS="$CPPFLAGS -ffreestanding"
 AC_CHECK_HEADER(mach/mach_types.h,,
                 [AC_MSG_ERROR([cannot find Mach headers])], -)
 CFLAGS=$old_CFLAGS
@@ -136,6 +135,4 @@ fi])
 
 hurd_MIG_RETCODE
 
-if test -n "$sysheaders"; then
-  CPPFLAGS=$OLD_CPPFLAGS
-fi
+CPPFLAGS=$OLD_CPPFLAGS