Make block title a menu parent link

I have a menu:

- Car Makers
-- Subaru
-- Mitsubishi
-- Nissan

In local_menu's output the names of the car makers are link. If leave the block title blank "Car Makers" becomes a plain text title of the block. I want that title to be a link, as though it was the related menu item.

Here's my patch. I suppose someone could turn this into a option in the block configuration screen. :)

If you supply a title in the block configuration screen the title will not be linked.