Hi, I am using GNU Guix now for a little while and since I started using it teeworlds did not build. So I invested some time and quickly found out that the package definition is simply missing a dependency (pkg-config) to build. You find a script which I used to create my working build as well as a patch for guix which I have not verified to  be working attached. It would be very nice if someone could investigate whether the patch is ok and commit it. Thanks, Tim Gesthuizen