Apple has updated X11 to version 1.1.2. The update weights 51.MB and brings the following enhancements:

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

X11 1.1.2 is available for download either through the Software Update utility or through Apple's support web site [1].