[libvirt] [PATCH] Improve compiler flag checking
# HG changeset patch
# User john.levon(a)sun.com
# Date 1229789393 28800
# Node ID a158bbc6df6fb8b15af875d08e73cfd3ca75f907
# Parent 34706075e6c801cd9532490c11b20b64dfcf464b
Improve compiler flag checking
Some compilers (including GCC) don't set the return value consistently
if an erroneous option is passed on the command line. Account for that.
Signed-off-by: John Levon <john.levon(a)sun.com>
diff --git a/acinclude.m4 b/acinclude.m4
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -45,21 +45,9 @@ AC_DEFUN([LIBVIRT_COMPILE_WARNINGS],[
;;
esac
- compiler_flags=
+ COMPILER_FLAGS=
for option in $try_compiler_flags; do
- SAVE_CFLAGS="$CFLAGS"
- CFLAGS="$CFLAGS $option"
- AC_MSG_CHECKING([whether gcc understands $option])
- AC_TRY_LINK([], [],
- has_option=yes,
- has_option=no,)
- CFLAGS="$SAVE_CFLAGS"
- AC_MSG_RESULT($has_option)
- if test $has_option = yes; then
- compiler_flags="$compiler_flags $option"
- fi
- unset has_option
- unset SAVE_CFLAGS
+ gl_COMPILER_FLAGS($option)
done
unset option
unset try_compiler_flags
@@ -85,7 +73,7 @@ AC_DEFUN([LIBVIRT_COMPILE_WARNINGS],[
fi
AC_MSG_RESULT($complCFLAGS)
- WARN_CFLAGS="$compiler_flags $complCFLAGS"
+ WARN_CFLAGS="$COMPILER_FLAGS $complCFLAGS"
AC_SUBST(WARN_CFLAGS)
dnl Needed to keep compile quiet on python 2.4
diff --git a/m4/compiler-flags.m4 b/m4/compiler-flags.m4
--- a/m4/compiler-flags.m4
+++ b/m4/compiler-flags.m4
@@ -25,10 +25,16 @@ AC_DEFUN([gl_COMPILER_FLAGS],
AC_SUBST(COMPILER_FLAGS)
ac_save_CFLAGS="$CFLAGS"
CFLAGS="$CFLAGS $1"
- AC_TRY_COMPILE(,
- [int x;],
- COMPILER_FLAGS="$COMPILER_FLAGS $1"
- AC_MSG_RESULT(yes),
- AC_MSG_RESULT(no))
- CFLAGS="$ac_save_CFLAGS"
+ AC_TRY_LINK([], [], has_option=yes, has_option=no,)
+ echo 'int x;' >conftest.c
+ $CC $CFLAGS -c conftest.c 2>conftest.err
+ ret=$?
+ if test $ret != 0 -o -s conftest.err -o $has_option = "no"; then
+ AC_MSG_RESULT(no)
+ else
+ AC_MSG_RESULT(yes)
+ COMPILER_FLAGS="$COMPILER_FLAGS $1"
+ fi
+ CFLAGS="$ac_save_CFLAGS"
+ rm -f conftest*
])