Please describe the problem:
Newer versions of pygtk require a number of functions which the quartz backend of GTK+ doesn't define. When one attempts to run a pygtk script, the dynamic linker gets mad because of undefined symbols, and refuses to run.

The attached patch adds stubs for the missing functions. Alternatively, we could have pygtk not use the missing functions--I have written a Ruby script which can make this automatic (http://vasi.dyndns.org:3128/trac/browser/gtk-osx/trunk/scripts/pygtk-missing.rb), I'll elaborate if anybody's interested.

Steps to reproduce:
1. Build pygtk against a GTK which uses the quartz backend.
2. Attempt to run any pygtk script, eg: pygtk-demo.


Actual results:
Dyld barfs:
ImportError: dlopen(/gtkosx/lib/python2.3/site-packages/gtk-2.0/gtk/_gtk.so, 2): Symbol not found: _gtk_clipboard_wait_for_rich_text
  Referenced from: /gtkosx/lib/python2.3/site-packages/gtk-2.0/gtk/_gtk.so
  Expected in: flat namespace


Expected results:
The script should run.

Does this happen every time?
Yes.

Other information: