Add -Wall,-Werror compiler flags

src/memory.c

@@ -115,6 +115,7 @@ void ucl_object_delete(struct ucl_object *obj) {
             break;
         case UCL_TYPE_INT:
         case UCL_TYPE_BUILTIN:
+        case UCL_TYPE_SPECIAL:
         case UCL_TYPE_COUNT:
             break;
     }