Clean up many strdups

src/utility.c

@@ -37,7 +37,7 @@ struct ucl_object *ucl_nil_create() {
 }
 
 struct ucl_object *ucl_t_create() {
-    return ucl_symbol_create(strdup("t"));
+    return ucl_symbol_create("t");
 }
 
 struct ucl_object *ucl_predicate(bool value) {