[PATCH 2/4] build: put compiler warnings in AM_CFLAGS, not CFLAGS

[Thomas Haller <thaller redhat com>]

From: Dan Winship <danw gnome org>

CFLAGS is supposed to be reserved for the user
---
 m4/compiler_warnings.m4 | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/m4/compiler_warnings.m4 b/m4/compiler_warnings.m4
index 3037c58..bdd603d 100644
--- a/m4/compiler_warnings.m4
+++ b/m4/compiler_warnings.m4
@@ -5,7 +5,7 @@ AC_DEFUN([NM_COMPILER_WARNINGS],
 AC_MSG_CHECKING(for more warnings)
 if test "$GCC" = "yes" -a "$set_more_warnings" != "no"; then
        AC_MSG_RESULT(yes)
-       CFLAGS="-Wall -std=gnu89 $CFLAGS"
+       AM_CFLAGS="-Wall -std=gnu89 $AM_CFLAGS"
 
        for option in -Wshadow -Wmissing-declarations -Wmissing-prototypes \
                      -Wdeclaration-after-statement \
@@ -20,17 +20,19 @@ if test "$GCC" = "yes" -a "$set_more_warnings" != "no"; then
                AC_TRY_COMPILE([], [],
                        has_option=yes,
                        has_option=no,)
-               if test $has_option = no; then
-                       CFLAGS="$SAVE_CFLAGS"
+               if test $has_option = yes; then
+                       AM_CFLAGS="$AM_CFLAGS $option"
                fi
+               CFLAGS="$SAVE_CFLAGS"
                AC_MSG_RESULT($has_option)
                unset has_option
                unset SAVE_CFLAGS
        done
        unset option
        if test "x$set_more_warnings" = xerror; then
-               CFLAGS="$CFLAGS -Werror"
+               AM_CFLAGS="$AM_CFLAGS -Werror"
        fi
+       AC_SUBST(AM_CFLAGS)
 else
        AC_MSG_RESULT(no)
 fi
-- 
2.5.0