static void wl_surface_frame_done(void *data, struct wl_callback *cb, uint32_t time)
{
   gfx_ctx_wayland_data_t *wl = (gfx_ctx_wayland_data_t*)data;

   wl->swap_complete = true;

   /* Destroy this callback */
   wl_callback_destroy(cb);
}

static const struct wl_callback_listener wl_surface_frame_listener = {
   .done = wl_surface_frame_done,
};

static void gfx_ctx_wl_swap_buffers(void *data)
{
   gfx_ctx_wayland_data_t *wl = (gfx_ctx_wayland_data_t*)data;

   struct wl_callback *cb = wl_surface_frame(wl->surface);

   wl_callback_add_listener(cb, &wl_surface_frame_listener, &wl);

   wl->swap_complete = false;

   egl_swap_buffers(&wl->egl);

   //while (!wl->swap_complete && wl_display_dispatch(wl->input.dpy)) {}

   while (!wl->swap_complete) {
      int ret = wl_display_dispatch(wl->input.dpy);
      if (!ret)
         break;
   }
}