FYI - I posted a more detail post in the Mac forum, but some of the dependencies won't install with Macports on 10.6 yet. If you compile, you may want to hold off on installing Mac OS X 10.6.
Luckily my wife's machine wasn't updated yet.... No dice. Even though I did the configure to disable radiant, making the UFOAI.app fails trying to copy in radiant.
Guess I am back to 2.2 because of the stairs issue is not corrected in any of the 2.3 binaries for OS X I can find to download.