glamor: supports GLES3 shaders

Konstantin requested to merge rilian-la-te/xserver:glamor-es3 into master

Also includes a commit which enables a GLES3 shaders by default if GLES, and modernizes a shading language a little bit.

Signed-off-by: Konstantin Pugin ria.freelander@gmail.com

Request for review: @ajax @anholt @p12tic @ofourdan

Edited by Konstantin

Merge request reports