Fixed bug with steam_tray icon not showing up on systems without the xpm gdk-pixbuf module.
We don't actually want to load any modules from the system in our case, so we'll build them all in.
The ani and gif modules are not built in because they change the ABI and we don't need them.
Allow Steam Runtime pulseaudio to connect to pulseaudio 3.0 on systems with XDG_RUNTIME_DIR set.