gcc gives an error on an unknown warning flag, but clang just gives a
warning. Upgrade the warning in clang to an error by activating
-Werror=unknown-warning-option if available.
Signed-off-by: Allan McRae
---
Tested with clang and gcc. Both give the right result.
m4/acinclude.m4 | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/m4/acinclude.m4 b/m4/acinclude.m4
index e601f0e..294507e 100644
--- a/m4/acinclude.m4
+++ b/m4/acinclude.m4
@@ -114,6 +114,10 @@ AC_DEFUN([CFLAGS_ADD],
[AS_VAR_PUSHDEF([my_cflags], [cflags_cv_warn_$1])dnl
AC_CACHE_CHECK([whether compiler handles $1], [my_cflags], [
save_CFLAGS="$CFLAGS"
+ CFLAGS="${CFLAGS} -Werror=unknown-warning-option"
+ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([])],
+ [],
+ [CFLAGS="$save_CFLAGS"])
CFLAGS="${CFLAGS} $1"
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([])],
[AS_VAR_SET([my_cflags], [yes])],
--
1.8.1.3