glxinfo shows: ERROR! sizeof(I830DRIRec) does not match passed size from device driver

[Sam Lawrance]

Running glxinfo gives me this error:

ERROR!  sizeof(I830DRIRec) does not match passed size from device driver

Googling around shows various suggestions about upgrading (mesa?)  
libraries, but I'm still lost.  The hardware is a mac mini with an  
intel GMA950.  The system is RELENG_6 from a few hours ago.  I  
installed xorg 7.2 from packages.

An xorg log is here: http://www.bsdtn.com/Xorg.0.log

Thanks for any help,
Sam