Reintroduce -Wall -Werror to check_seapp.

Also add attribute for a potential unused
function argument when dealing with darwin
SDK builds.

Change-Id: Iefdbecb050cc5fff6036f15413566e10cefa3813
diff --git a/tools/Android.mk b/tools/Android.mk
index 9461c2b..727a4d3 100644
--- a/tools/Android.mk
+++ b/tools/Android.mk
@@ -5,7 +5,7 @@
 LOCAL_MODULE := checkseapp
 LOCAL_MODULE_TAGS := optional
 LOCAL_C_INCLUDES := external/libsepol/include/
-LOCAL_CFLAGS := -DLINK_SEPOL_STATIC
+LOCAL_CFLAGS := -DLINK_SEPOL_STATIC -Wall -Werror
 LOCAL_SRC_FILES := check_seapp.c
 LOCAL_STATIC_LIBRARIES := libsepol
 
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;