diff --git a/acinclude.m4 b/acinclude.m4
index caa09e8b..4d09dc6e 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -22,6 +22,7 @@ AC_DEFUN([COMPILER_FLAGS], [
 		CFLAGS+=" -Wdeclaration-after-statement"
 		CFLAGS+=" -Wmissing-declarations"
 		CFLAGS+=" -Wredundant-decls"
+		CFLAGS+=" -Wformat -Wformat-security"
 		if ( $CC -v 2>/dev/null | grep "gcc version" ); then
 			CFLAGS+=" -Wcast-align"
 		fi