glsl: add OES_texture_buffer and EXT_texture_buffer support

Expose the samplerBuffer/imageBuffer types, and allow the various
functions to operate on them.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
6 files changed