Merge p3yk branch with the trunk up to revision 45595. This breaks a fair
number of tests, all because of the codecs/_multibytecodecs issue described
here (it's not a Py3K issue, just something Py3K discovers):
http://mail.python.org/pipermail/python-dev/2006-April/064051.html

Hye-Shik Chang promised to look for a fix, so no need to fix it here. The
tests that are expected to break are:

test_codecencodings_cn
test_codecencodings_hk
test_codecencodings_jp
test_codecencodings_kr
test_codecencodings_tw
test_codecs
test_multibytecodec

This merge fixes an actual test failure (test_weakref) in this branch,
though, so I believe merging is the right thing to do anyway.
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index 9494062..561ba4a5 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -377,13 +377,7 @@
 descr_traverse(PyObject *self, visitproc visit, void *arg)
 {
 	PyDescrObject *descr = (PyDescrObject *)self;
-	int err;
-
-	if (descr->d_type) {
-		err = visit((PyObject *)(descr->d_type), arg);
-		if (err)
-			return err;
-	}
+	Py_VISIT(descr->d_type);
 	return 0;
 }
 
@@ -480,7 +474,7 @@
 	0,					/* tp_as_sequence */
 	0,					/* tp_as_mapping */
 	0,					/* tp_hash */
-	(ternaryfunc)0,				/* tp_call */
+	0,					/* tp_call */
 	0,					/* tp_str */
 	PyObject_GenericGetAttr,		/* tp_getattro */
 	0,					/* tp_setattro */
@@ -518,7 +512,7 @@
 	0,					/* tp_as_sequence */
 	0,					/* tp_as_mapping */
 	0,					/* tp_hash */
-	(ternaryfunc)0,				/* tp_call */
+	0,					/* tp_call */
 	0,					/* tp_str */
 	PyObject_GenericGetAttr,		/* tp_getattro */
 	0,					/* tp_setattro */
@@ -814,13 +808,7 @@
 proxy_traverse(PyObject *self, visitproc visit, void *arg)
 {
 	proxyobject *pp = (proxyobject *)self;
-	int err;
-
-	if (pp->dict) {
-		err = visit(pp->dict, arg);
-		if (err)
-			return err;
-	}
+	Py_VISIT(pp->dict);
 	return 0;
 }
 
@@ -999,18 +987,8 @@
 wrapper_traverse(PyObject *self, visitproc visit, void *arg)
 {
 	wrapperobject *wp = (wrapperobject *)self;
-	int err;
-
-	if (wp->descr) {
-		err = visit((PyObject *)(wp->descr), arg);
-		if (err)
-			return err;
-	}
-	if (wp->self) {
-		err = visit(wp->self, arg);
-		if (err)
-			return err;
-	}
+	Py_VISIT(wp->descr);
+	Py_VISIT(wp->self);
 	return 0;
 }
 
@@ -1237,20 +1215,10 @@
 property_traverse(PyObject *self, visitproc visit, void *arg)
 {
 	propertyobject *pp = (propertyobject *)self;
-	int err;
-
-#define VISIT(SLOT) \
-	if (pp->SLOT) { \
-		err = visit((PyObject *)(pp->SLOT), arg); \
-		if (err) \
-			return err; \
-	}
-
-	VISIT(prop_get);
-	VISIT(prop_set);
-	VISIT(prop_del);
-	VISIT(prop_doc);
-
+	Py_VISIT(pp->prop_get);
+	Py_VISIT(pp->prop_set);
+	Py_VISIT(pp->prop_del);
+	Py_VISIT(pp->prop_doc);
 	return 0;
 }