Fix build against wayland 1.20

Fixes #5088

src/video/wayland/SDL_waylanddyn.h

@@ -95,6 +95,8 @@ void SDL_WAYLAND_UnloadSymbols(void);
 #define wl_proxy_marshal_constructor_versioned (*WAYLAND_wl_proxy_marshal_constructor_versioned)
 #define wl_proxy_set_tag (*WAYLAND_wl_proxy_set_tag)
 #define wl_proxy_get_tag (*WAYLAND_wl_proxy_get_tag)
+#define wl_proxy_marshal_flags (*WAYLAND_wl_proxy_marshal_flags)
+#define wl_proxy_marshal_array_flags (*WAYLAND_wl_proxy_marshal_array_flags)
 
 #define wl_seat_interface (*WAYLAND_wl_seat_interface)
 #define wl_surface_interface (*WAYLAND_wl_surface_interface)

src/video/wayland/SDL_waylandsym.h

@@ -84,6 +84,10 @@ SDL_WAYLAND_MODULE(WAYLAND_CLIENT_1_18)
 SDL_WAYLAND_SYM(void, wl_proxy_set_tag, (struct wl_proxy *, const char * const *))
 SDL_WAYLAND_SYM(const char * const *, wl_proxy_get_tag, (struct wl_proxy *))
 
+SDL_WAYLAND_MODULE(WAYLAND_CLIENT_1_20)
+SDL_WAYLAND_SYM(struct wl_proxy*, wl_proxy_marshal_flags, (struct wl_proxy *proxy, uint32_t opcode, const struct wl_interface *interfac, uint32_t version, uint32_t flags, ...))
+SDL_WAYLAND_SYM(struct wl_proxy*, wl_proxy_marshal_array_flags, (struct wl_proxy *proxy, uint32_t opcode, const struct wl_interface *interface, uint32_t version,  uint32_t flags, union wl_argument *args))
+
 SDL_WAYLAND_INTERFACE(wl_seat_interface)
 SDL_WAYLAND_INTERFACE(wl_surface_interface)
 SDL_WAYLAND_INTERFACE(wl_shm_pool_interface)