The main argument against approving the patch, seems to be, that one would expect static scoping rules to apply to the anonymous function. After all, this is the case in similar languages, which support anonymous functions. One could only assume, that changing PHP to support this, would be a major undertaking.
One would be wrong, it seems.
A patch has been made to add the functionality (from Christian Seller) adding a new keyword, lexical, to make it all work.