bug#43728: teeworlds missing sound

[bdju]

I don't hear any music or sound effects when playing teeworlds.
guix (GNU Guix) 7806e568f6c61b97660e91f4f97dfbb9e81b9e06
It was my first time playing, so I have no way of knowing if it used to
have sound or not. There's a keybind to toggle sound and it doesn't
change anything.