Get rid of most of the flags (in tp_flags) that keep track of various
variations of the type struct and its attachments.  In Py3k, all type
structs have to have all fields -- no binary backwards compatibility.
Had to change the complex object to a new-style number!
diff --git a/Objects/setobject.c b/Objects/setobject.c
index 26a232b..91682a2 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -1819,7 +1819,7 @@
 	PyObject_GenericGetAttr,	/* tp_getattro */
 	0,				/* tp_setattro */
 	0,				/* tp_as_buffer */
-	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_CHECKTYPES |
+	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
 		Py_TPFLAGS_BASETYPE,	/* tp_flags */
 	set_doc,			/* tp_doc */
 	(traverseproc)set_traverse,	/* tp_traverse */
@@ -1913,7 +1913,7 @@
 	PyObject_GenericGetAttr,	/* tp_getattro */
 	0,				/* tp_setattro */
 	0,				/* tp_as_buffer */
-	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_CHECKTYPES |
+	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
 		Py_TPFLAGS_BASETYPE,	/* tp_flags */
 	frozenset_doc,			/* tp_doc */
 	(traverseproc)set_traverse,	/* tp_traverse */