Issue #1717: rename tp_compare to tp_reserved.  I'll change the
type of tp_compare in a separate commit, for ease of reversion
should things go wrong.
diff --git a/Objects/cobject.c b/Objects/cobject.c
index c437491..e9b71df 100644
--- a/Objects/cobject.c
+++ b/Objects/cobject.c
@@ -137,7 +137,7 @@
     0,				/*tp_print*/
     0,				/*tp_getattr*/
     0,				/*tp_setattr*/
-    0,				/*tp_compare*/
+    0,				/*tp_reserved*/
     0,				/*tp_repr*/
     0,				/*tp_as_number*/
     0,				/*tp_as_sequence*/