diff -r 27edae50e62c Modules/_futuresmodule.c
--- a/Modules/_futuresmodule.c	Sun Oct 09 20:19:21 2016 -0700
+++ b/Modules/_futuresmodule.c	Tue Oct 11 01:59:22 2016 +0900
@@ -943,7 +943,7 @@
     }
     Py_INCREF(fut);
     it->future = (FutureObj*)fut;
-    _PyObject_GC_TRACK(it);
+    PyObject_GC_Track(it);
     return (PyObject*)it;
 }