The attached patch for setuptools 0.6c9 replaces a shell callout to
/usr/bin/sw_vers to using platform.mac_ver on OSX.
The primary reason for writing the patch is that gdb tends to cause havoc with
calls to os.popen (the debugged process gets an signal and debugging gets
This patch makes it a lot more convenient to run "setup.py test" in a gdb
session, without this patch I regularly have to re-run the tests several times
until the callout to sw_vers succeeds.