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/_bytesio.c b/Modules/_bytesio.c
index 48fe50a..2cea0fc 100644
--- a/Modules/_bytesio.c
+++ b/Modules/_bytesio.c
@@ -698,7 +698,7 @@
     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*/