static struct vrend_linked_shader_program *lookup_cs_shader_program(struct vrend_context *ctx,
                                                                    GLuint cs_id)
{
   struct vrend_linked_shader_program *ent;
   LIST_FOR_EACH_ENTRY(ent, &ctx->sub->cs_programs, head) {
      if (ent->ss[PIPE_SHADER_COMPUTE]->id == cs_id) {
         list_del(&ent->head);
         list_add(&ent->head, &ctx->sub->cs_programs);
         return ent;
      }
   }
   return NULL;
}
static struct vrend_linked_shader_program *lookup_cs_shader_program(struct vrend_context *ctx,
                                                                    GLuint cs_id)
{
   struct vrend_linked_shader_program *ent;
   LIST_FOR_EACH_ENTRY(ent, &ctx->sub->cs_programs, head) {
      if (ent->ss[PIPE_SHADER_COMPUTE]->id == cs_id) {
         list_del(&ent->head);
         list_add(&ent->head, &ctx->sub->cs_programs);
         return ent;
      }
   }
   return NULL;
}