Use PyErr_WarnPy3k throughout
diff --git a/Objects/listobject.c b/Objects/listobject.c
index 81617e4..e4e8ae4 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -2038,9 +2038,7 @@
 	if (compare == Py_None)
 		compare = NULL;
 	if (compare != NULL && 
-            Py_Py3kWarningFlag &&
-	    PyErr_Warn(PyExc_DeprecationWarning, 
-		       "the cmp argument is not supported in 3.x") < 0)
+            PyErr_WarnPy3k("the cmp argument is not supported in 3.x", 1) < 0)
 		return NULL;
 	if (keyfunc == Py_None)
 		keyfunc = NULL;