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/Modules/_pickle.c b/Modules/_pickle.c
index 1036367..4976cc5 100644
--- a/Modules/_pickle.c
+++ b/Modules/_pickle.c
@@ -2677,7 +2677,7 @@
     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*/
@@ -4534,7 +4534,7 @@
     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*/