For those not closely watching the Mesa Git tree, just hours ago the Mesa GLSL-To-TGSI translator was merged to master, making it a feature for the next Mesa 7.12 (or potentially Mesa 8.0) release.
For those that don't know what the GLSL to TGSI translator is all about, see this Phoronix article
or the various other posts
about this work.
The merge to master happened as part of this commit