Add page about enabling Indirect GLX for Linux and Mac
See this page for details. Instructions for re-enabling it are on this page. For newer Xorg versions, there is also a config flag that is easier to use:
[acaprez@rcf-acaprez xorg.conf.d]$ cat /etc/X11/xorg.conf.d/iglx.conf
Section "ServerFlags"
Option "IndirectGLX" "on"
EndSection