glsl: Add extension plumbing for ARB_fragment_layer_viewport

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>

src/glsl/glsl_parser_extras.cpp

@@ -517,6 +517,7 @@ static const _mesa_glsl_extension _mesa_glsl_supported_extensions[] = {
    EXT(ARB_explicit_attrib_location,   true,  false,     ARB_explicit_attrib_location),
    EXT(ARB_explicit_uniform_location,  true,  false,     ARB_explicit_uniform_location),
    EXT(ARB_fragment_coord_conventions, true,  false,     ARB_fragment_coord_conventions),
+   EXT(ARB_fragment_layer_viewport,    true,  false,     ARB_fragment_layer_viewport),
    EXT(ARB_gpu_shader5,                true,  false,     ARB_gpu_shader5),
    EXT(ARB_sample_shading,             true,  false,     ARB_sample_shading),
    EXT(ARB_separate_shader_objects,    true,  false,     dummy_true),

src/glsl/glsl_parser_extras.h

@@ -382,6 +382,8 @@ struct _mesa_glsl_parse_state {
    bool ARB_explicit_uniform_location_warn;
    bool ARB_fragment_coord_conventions_enable;
    bool ARB_fragment_coord_conventions_warn;
+   bool ARB_fragment_layer_viewport_enable;
+   bool ARB_fragment_layer_viewport_warn;
    bool ARB_gpu_shader5_enable;
    bool ARB_gpu_shader5_warn;
    bool ARB_sample_shading_enable;

src/glsl/standalone_scaffolding.cpp

@@ -98,6 +98,7 @@ void initialize_context_to_defaults(struct gl_context *ctx, gl_api api)
    ctx->Extensions.ARB_ES3_compatibility = true;
    ctx->Extensions.ARB_explicit_attrib_location = true;
    ctx->Extensions.ARB_fragment_coord_conventions = true;
+   ctx->Extensions.ARB_fragment_layer_viewport = true;
    ctx->Extensions.ARB_gpu_shader5 = true;
    ctx->Extensions.ARB_sample_shading = true;
    ctx->Extensions.ARB_shader_bit_encoding = true;