[mythtv] OpenGL + display resolution change == video freeze

[John Patrick Poet]

If OpenGL is used without XrandR, or XrandR is used without OpenGL, then 
the Guide can be brought up while watching live TV.

If both OpenGL and XrandR are enabled, then bringing up the Guide in 
Live TV caused the video to freeze.

I finally tracked down the problem to glXWaitVideoSyncSGI().  After a 
video display resolution change, then next call to glXWaitVideoSyncSGI() 
*never* returns.

Knowing nothing about OpenGL, I don't know what to do about this.  Just 
thought I would throw this information out there in case someone with 
more knowledge wants to take a crack at the problem.

John