diff --git a/configure.ac b/configure.ac
index 83d28b85..d83b148a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1130,7 +1130,7 @@ AS_IF([test "$GCC" = yes], [
 		OLD_CFLAGS="$CFLAGS"
 		CFLAGS="$CFLAGS $NEW_FLAG -Werror"
 		AC_COMPILE_IFELSE([AC_LANG_SOURCE(
-				[void foo(void); void foo(void) { }])], [
+				[[void foo(void); void foo(void) { }]])], [
 			AM_CFLAGS="$AM_CFLAGS $NEW_FLAG"
 			AC_MSG_RESULT([yes])
 		], [