git clone --recursive https://github.com/flathub/com.stepmania.StepMania  /tmp/com.stepmania.StepMania
docker run -ti --privileged --name=buildflatpackstepmania -v /tmp/com.stepmania.StepMania:/flat ubuntu:18.04
cd /flat/
apt-get update && apt-get install -y git build-essential flatpak-builder ostree fuse elfutils ca-certificates --no-install-recommends
mkdir /build
cd /build
flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
flatpak install flathub org.gnome.Sdk//3.36
flatpak install flathub org.gnome.Platform//3.36
export FLATPAK_GL_DRIVERS=dummy
flatpak-builder --force-clean --disable-rofiles-fuse /build com.stepmania.StepMania.json