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/setobject.c b/Objects/setobject.c
index 3dc396c..8ecc405 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -876,7 +876,7 @@
 	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 */
@@ -2104,7 +2104,7 @@
 	0,				/* tp_print */
 	0,				/* tp_getattr */
 	0,				/* tp_setattr */
-	0,				/* tp_compare */
+	0,				/* tp_reserved */
 	(reprfunc)set_repr,		/* tp_repr */
 	&set_as_number,			/* tp_as_number */
 	&set_as_sequence,		/* tp_as_sequence */
@@ -2201,7 +2201,7 @@
 	0,				/* tp_print */
 	0,				/* tp_getattr */
 	0,				/* tp_setattr */
-	0,				/* tp_compare */
+	0,				/* tp_reserved */
 	(reprfunc)set_repr,		/* tp_repr */
 	&frozenset_as_number,		/* tp_as_number */
 	&set_as_sequence,		/* tp_as_sequence */