glsl: Add built-in functions for GLSL 1.50.

glsl: Add built-in functions for GLSL 1.50.

This makes basic built-in functions work in GLSL 1.50.  It supports
everything except the new Geometry Shader functions.

The new 150.glsl file is 140.glsl plus ARB_texture_multisample.glsl;
150.frag is identical to 140.frag except for the #version bump.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Chris Forbes <chrisf@ijw.co.nz>