Use PyErr_WarnPy3k throughout
diff --git a/Objects/cellobject.c b/Objects/cellobject.c
index 46955ab..e2a8d29 100644
--- a/Objects/cellobject.c
+++ b/Objects/cellobject.c
@@ -55,9 +55,8 @@
 cell_compare(PyCellObject *a, PyCellObject *b)
 {
 	/* Py3K warning for comparisons  */
-	if (Py_Py3kWarningFlag &&
-	    PyErr_Warn(PyExc_DeprecationWarning,
-		       "cell comparisons not supported in 3.x") < 0) {
+	if (PyErr_WarnPy3k("cell comparisons not supported in 3.x",
+                           1) < 0) {
 		return -2;
 	}