Also, addendum: Just before upgrading xf86-video-intel, I tagged the tree so that we can back it out easily if necessary, or, if you don't want to deal with the fallout, you can easily revert it locally. The tag is riastradh-xf86-video-intel-2-7-1-pre-2-21-15, and the affected directories are
src/distrib/sets/lists/xdebug src/distrib/sets/lists/xserver src/external/mit/xorg/server/drivers/xf86-video-intel xsrc/external/mit/xf86-video-intel
