By GuestXcode 1.2 project file ( that goes into a sys/osx directory next to game/ and d3xp/ ). The current SDK source was used as is to produce Mac game binaries. Note that the current Mac release ( 1.3 ) will not load any content from d3xp/, this is by design until Aspyr gets to shipping the expansion pack for Mac. So please refrain to try putting stuff together with d3xp code for Mac until then.
We used XCode 1.2 and gcc 3.3 to produce Mac game bins ( all of that on 10.3, I don't think we've had to compile binaries under 10.4 yet, and the stuff we did on 10.3 works fine with 10.4 ). What I would recommend rather than using XCode though, is to adapt the scons scripts to recognize the Darwin platform and compile from scons. Specially for building dylibs, it's very easy ( I do that for our next project, I hate XCode ).