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/funcobject.c b/Objects/funcobject.c
index 00ae2eb..59cb519 100644
--- a/Objects/funcobject.c
+++ b/Objects/funcobject.c
@@ -466,47 +466,14 @@
 static int
 func_traverse(PyFunctionObject *f, visitproc visit, void *arg)
 {
-	int err;
-	if (f->func_code) {
-		err = visit(f->func_code, arg);
-		if (err)
-			return err;
-	}
-	if (f->func_globals) {
-		err = visit(f->func_globals, arg);
-		if (err)
-			return err;
-	}
-	if (f->func_module) {
-		err = visit(f->func_module, arg);
-		if (err)
-			return err;
-	}
-	if (f->func_defaults) {
-		err = visit(f->func_defaults, arg);
-		if (err)
-			return err;
-	}
-	if (f->func_doc) {
-		err = visit(f->func_doc, arg);
-		if (err)
-			return err;
-	}
-	if (f->func_name) {
-		err = visit(f->func_name, arg);
-		if (err)
-			return err;
-	}
-	if (f->func_dict) {
-		err = visit(f->func_dict, arg);
-		if (err)
-			return err;
-	}
-	if (f->func_closure) {
-		err = visit(f->func_closure, arg);
-		if (err)
-			return err;
-	}
+	Py_VISIT(f->func_code);
+	Py_VISIT(f->func_globals);
+	Py_VISIT(f->func_module);
+	Py_VISIT(f->func_defaults);
+	Py_VISIT(f->func_doc);
+	Py_VISIT(f->func_name);
+	Py_VISIT(f->func_dict);
+	Py_VISIT(f->func_closure);
 	return 0;
 }
 
@@ -647,17 +614,14 @@
 static int
 cm_traverse(classmethod *cm, visitproc visit, void *arg)
 {
-	if (!cm->cm_callable)
-		return 0;
-	return visit(cm->cm_callable, arg);
+	Py_VISIT(cm->cm_callable);
+	return 0;
 }
 
 static int
 cm_clear(classmethod *cm)
 {
-	Py_XDECREF(cm->cm_callable);
-	cm->cm_callable = NULL;
-
+	Py_CLEAR(cm->cm_callable);
 	return 0;
 }
 
@@ -808,9 +772,8 @@
 static int
 sm_traverse(staticmethod *sm, visitproc visit, void *arg)
 {
-	if (!sm->sm_callable)
-		return 0;
-	return visit(sm->sm_callable, arg);
+	Py_VISIT(sm->sm_callable);
+	return 0;
 }
 
 static int