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/parsermodule.c b/Modules/parsermodule.c
index 32de6bc..38ec65e 100644
--- a/Modules/parsermodule.c
+++ b/Modules/parsermodule.c
@@ -203,7 +203,7 @@
     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       */