I want to inform you that someone created the unofficial version of Gothic that you can compile on Mac OS X (Intel):
Unfortunately, the current version of Gothic is not the fully playable version of this game. However, you can see that people are actively working on this project:
I haven't tried it yet. You can join the project if you want to run it and report bugs in the current release of this game.
Perhaps, some users would be interested in developing REGoth for Mac.