Re: [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&gt;

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* ])