wayland: Expose xdg_toplevel to SysWM

include/SDL_syswm.h

@@ -292,6 +292,7 @@ struct SDL_SysWMinfo
             void *shell_surface;                    /**< DEPRECATED Wayland shell_surface (window manager handle) */
             struct wl_egl_window *egl_window;       /**< Wayland EGL window (native window) */
             struct xdg_surface *xdg_surface;        /**< Wayland xdg surface (window manager handle) */
+            struct xdg_toplevel *xdg_toplevel;      /**< Wayland xdg toplevel role */
         } wl;
 #endif
 #if defined(SDL_VIDEO_DRIVER_MIR)  /* no longer available, left for API/ABI compatibility. Remove in 2.1! */