[gtk+osx] Improved mpouse tracking patch

[David B. <va...@nt...>]

I've just added an improved version of my mouse tracking patch
(patch request 869989)  to the project patch repository.

To make a long story short,it improves GDK so that GIMP will
paint and select properly, even if you move the cursor off
the GIMP canvas over other gdk_windows, like scroll bars and
status bars whilst painting.

You need to apply it to the CVS code.

Dave