I see that X11 for Mac OS X has been updated, it can be downloaded here.
Little information other than.
About this update
This update addresses several issues in the X11 for Mac OS X package, enabling it to better handle:
- GLX stereo visuals - offscreen rendering to GLX Pbuffers and Pixmaps
To tell X11 to take advantage of stereo visuals, enter: $ defaults write com.apple.x11 enable_stereo -bool true