Mac OSX keyboard input fails for custom layouts

[Nikolaj Schumacher]

In Mac OSX there are two kind of keyboard resources: classic and
unicode. XML .keylayout files only provide a unicode resource and
Emacs currently only uses the classic resource. As a result keys
pressed with modifiers will result in a completely wrong key (while
normal text input works correctly).

I've written a short patch for emacs-20.0.50.2 which solved the issue
for me. It should be rather save to include since most of the code is
only executed when no classic resource is available anyway. However
it will only work on OSX >= 10.2. Is that implied by #define MAC_OSX?
Some of the code I've seen seemed to suggest that. If not, how do I
check for it?

regards,
Nikolaj Schumacher