mesa: move ShaderCompilerOptions into gl_constants

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>

src/glsl/link_varyings.cpp

@@ -329,7 +329,7 @@ tfeedback_decl::init(struct gl_context *ctx, const void *mem_ctx,
     * class must behave specially to account for the fact that gl_ClipDistance
     * is converted from a float[8] to a vec4[2].
     */
-   if (ctx->ShaderCompilerOptions[MESA_SHADER_VERTEX].LowerClipDistance &&
+   if (ctx->Const.ShaderCompilerOptions[MESA_SHADER_VERTEX].LowerClipDistance &&
        strcmp(this->var_name, "gl_ClipDistance") == 0) {
       this->is_clip_distance_mesa = true;
    }