(Slightly modified) patch by Steve Spicklemire to make Python build

out of the box on OSX 10.1. Untested by me (except for not having adverse
effects on 10.0.4) but it looks good, for now. Eventually we should not
trigger on the darwin version but test for something, but until I have
the time to install 10.1 myself I have no clue what to test on.

It would be nice if this got in to the 2.2a3 distribution.