From 29ad07504badce1327007185a0efdae4a4509d69 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Tue, 24 Feb 2015 17:49:48 +0100 Subject: [PATCH] from systemd: build: make sure to test for -Wflag instead of -Wno-flag gcc does not support testing for negated warnings. See here for details: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63499 This patch changes CC_CHECK_FLAG_APPEND to always test for the non-negated warnings. --- m4/attributes.m4 | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/m4/attributes.m4 b/m4/attributes.m4 index ab4b785..bfdb50f 100644 --- a/m4/attributes.m4 +++ b/m4/attributes.m4 @@ -34,14 +34,15 @@ dnl this special exception to the GPL to apply to your modified version as dnl well. dnl Check if FLAG in ENV-VAR is supported by compiler and append it -dnl to WHERE-TO-APPEND variable +dnl to WHERE-TO-APPEND variable. Note that we invert -Wno-* checks to +dnl -W* as gcc cannot test for negated warnings. dnl CC_CHECK_FLAG_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG]) AC_DEFUN([CC_CHECK_FLAG_APPEND], [ AC_CACHE_CHECK([if $CC supports flag $3 in envvar $2], AS_TR_SH([cc_cv_$2_$3]), [eval "AS_TR_SH([cc_save_$2])='${$2}'" - eval "AS_TR_SH([$2])='-Werror $3'" + eval "AS_TR_SH([$2])='-Werror `echo "$3" | sed 's/^-Wno-/-W/'`'" AC_LINK_IFELSE([AC_LANG_SOURCE([int main(void) { return 0; } ])], [eval "AS_TR_SH([cc_cv_$2_$3])='yes'"], [eval "AS_TR_SH([cc_cv_$2_$3])='no'"])