diff --git a/tools/check_seapp.c b/tools/check_seapp.c
index ed781bf..19e2ab2 100644
--- a/tools/check_seapp.c
+++ b/tools/check_seapp.c
@@ -436,7 +436,8 @@
  * @param rm
  * 	rule map to be freed.
  */
-static void rule_map_free(rule_map *rm, rule_map_switch s) {
+static void rule_map_free(rule_map *rm,
+		rule_map_switch s __attribute__((unused)) /* only glibc builds, ignored otherwise */) {
 
 	size_t i;
 	size_t len = rm->length;