--- a/mercurial/parsers.c	Wed Aug 12 17:01:50 2015 -0500
+++ b/mercurial/parsers.c	Thu Aug 13 17:58:33 2015 +0900
@@ -1144,7 +1144,7 @@
 		includepath = 1;
 
 	/* Initialize return set */
-	reachable = PySet_New(0);
+	reachable = PySet_New(NULL);
 	if (reachable == NULL) {
 		PyErr_NoMemory();
 		goto bail;