Attempt to configure for Wayland

mame.ini

@@ -30,4 +30,9 @@ share_directory           $HOME/.mame/share
 #
 # OSD VIDEO OPTIONS
 #
-video                     opengl
+video                     bgfx
+
+#
+# BGFX POST-PROCESSING OPTIONS
+#
+bgfx_path                 /app/share/mame/bgfx

org.mamedev.MAME.yaml

@@ -11,6 +11,7 @@ finish-args:
   - --filesystem=host:ro
   - --share=network
   - --share=ipc
+  - --socket=x11
   - --socket=fallback-x11
   - --socket=pulseaudio
   - --socket=wayland
@@ -25,6 +26,7 @@ modules:
       - make
           -j ${FLATPAK_BUILDER_N_JOBS}
           CFLAGS+=-Wno-error=restrict
+          USE_WAYLAND=1
           USE_SYSTEM_LIB_FLAC=1
           SDL_INI_PATH='$$HOME/.APP_NAME;/app/share/APP_NAME/ini'
           LDOPTS=-Wl,-s