Eric Anholt has been working on completely overhauling the Raspberry Graphics Stack since July 2014. This means it was done "properly" - everything is opensource and directly in upstream: kernel.org, mesa3d.org, x.org etc. This also means everything using OpenGL inside X (GLX) automatically started working as soon his efforts flowed down into Raspbian !
As of 2018, his work is already included in Raspbian but disabled by default.
Some stability issues remain. Start raspi-config and go to "Advanced options".
You can follow Erics trials and tribulations on his blog "This week in VC4
" ("VideoCore 4" is the name of the Raspberry Pi GPU)