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/_dbmmodule.c b/Modules/_dbmmodule.c
index 80c73bf..885c3aa 100644
--- a/Modules/_dbmmodule.c
+++ b/Modules/_dbmmodule.c
@@ -337,7 +337,7 @@
 	0,			  /*tp_print*/
 	0,                        /*tp_getattr*/
 	0,			  /*tp_setattr*/
-	0,			  /*tp_compare*/
+	0,			  /*tp_reserved*/
 	0,			  /*tp_repr*/
 	0,			  /*tp_as_number*/
 	&dbm_as_sequence,	  /*tp_as_sequence*/