audio/dbus: Fix building with modules on macOS

When configuring QEMU with --enable-modules we get on macOS:

  --- stderr ---
  Dependency ui-dbus cannot be satisfied

ui-dbus depends on pixman and opengl, so add these dependencies
to audio-dbus.

Fixes: 739362d ("audio: add "dbus" audio backend")
Reviewed-by: Li Zhang <lizhang@suse.de>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

audio/meson.build

@@ -28,7 +28,7 @@ endforeach
 
 if dbus_display
     module_ss = ss.source_set()
-    module_ss.add(when: gio, if_true: files('dbusaudio.c'))
+    module_ss.add(when: [gio, pixman, opengl, 'CONFIG_GIO'], if_true: files('dbusaudio.c'))
     audio_modules += {'dbus': module_ss}
 endif