Use PyErr_WarnPy3k throughout
diff --git a/Objects/bufferobject.c b/Objects/bufferobject.c
index f4c69a0..37d9bcb 100644
--- a/Objects/bufferobject.c
+++ b/Objects/bufferobject.c
@@ -233,9 +233,7 @@
 	Py_ssize_t offset = 0;
 	Py_ssize_t size = Py_END_OF_BUFFER;
 
-	if (Py_Py3kWarningFlag &&
-	    PyErr_WarnEx(PyExc_DeprecationWarning,
-			 "buffer() not supported in 3.x; "
+	if (PyErr_WarnPy3k("buffer() not supported in 3.x; "
 			 "use memoryview()", 1) < 0)
 		return NULL;