wayland: Fix building without Vulkan support

src/video/wayland/SDL_waylandvideo.h

@@ -92,6 +92,9 @@ typedef struct {
     SDL_bool done;
 } SDL_WaylandOutputData;
 
+/* Needed to get wl_surface declaration, fixes GitHub#4594 */
+#include "SDL_waylanddyn.h"
+
 extern void SDL_WAYLAND_register_surface(struct wl_surface *surface);
 extern void SDL_WAYLAND_register_output(struct wl_output *output);
 extern SDL_bool SDL_WAYLAND_own_surface(struct wl_surface *surface);