mesa: expose ARB_tessellation_shader in the compatibility profile

Gallium drivers don't expose this yet due to:
    "st/mesa: use PIPE_CAP_GLSL_FEATURE_LEVEL_COMPATIBILITY"

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>

src/mesa/drivers/dri/i965/intel_extensions.c

@@ -236,7 +236,8 @@ intelInitExtensions(struct gl_context *ctx)
       ctx->Extensions.ARB_shader_image_size = true;
       ctx->Extensions.ARB_shader_precision = true;
       ctx->Extensions.ARB_shader_texture_image_samples = true;
-      ctx->Extensions.ARB_tessellation_shader = true;
+      if (ctx->API != API_OPENGL_COMPAT)
+         ctx->Extensions.ARB_tessellation_shader = true;
       ctx->Extensions.ARB_texture_compression_bptc = true;
       ctx->Extensions.ARB_texture_view = true;
       ctx->Extensions.ARB_shader_storage_buffer_object = true;

src/mesa/main/extensions_table.h

@@ -132,7 +132,7 @@ EXT(ARB_shadow                              , ARB_shadow
 EXT(ARB_sparse_buffer                       , ARB_sparse_buffer                      , GLL, GLC,  x ,  x , 2014)
 EXT(ARB_stencil_texturing                   , ARB_stencil_texturing                  , GLL, GLC,  x ,  x , 2012)
 EXT(ARB_sync                                , ARB_sync                               , GLL, GLC,  x ,  x , 2003)
-EXT(ARB_tessellation_shader                 , ARB_tessellation_shader                ,  x , GLC,  x ,  x , 2009)
+EXT(ARB_tessellation_shader                 , ARB_tessellation_shader                , GLL, GLC,  x ,  x , 2009)
 EXT(ARB_texture_barrier                     , NV_texture_barrier                     , GLL, GLC,  x ,  x , 2014)
 EXT(ARB_texture_border_clamp                , ARB_texture_border_clamp               , GLL,  x ,  x ,  x , 2000)
 EXT(ARB_texture_buffer_object               , ARB_texture_buffer_object              , GLL, GLC,  x ,  x , 2008)

src/mesa/state_tracker/st_extensions.c

@@ -1020,8 +1020,10 @@ void st_init_extensions(struct pipe_screen *screen,
 
    /* Below are the cases which cannot be moved into tables easily. */
 
+   /* The compatibility profile also requires GLSLVersionCompat >= 400. */
    if (screen->get_shader_param(screen, PIPE_SHADER_TESS_CTRL,
-                                PIPE_SHADER_CAP_MAX_INSTRUCTIONS) > 0) {
+                                PIPE_SHADER_CAP_MAX_INSTRUCTIONS) > 0 &&
+       (api != API_OPENGL_COMPAT || consts->GLSLVersionCompat >= 400)) {
       extensions->ARB_tessellation_shader = GL_TRUE;
    }