newclassobject() gets a third argument
diff --git a/Python/ceval.c b/Python/ceval.c
index 1c8f3af..76869ff 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1524,5 +1524,5 @@
 		err_setstr(SystemError, "build_class with non-dictionary");
 		return NULL;
 	}
-	return newclassobject(v, w);
+	return newclassobject(v, w, (object *) NULL);
 }