In order to execute the installers build MojoSetup:
git clone https://github.com/icculus/mojosetup.git
mkdir mojosetup/build
cd mojosetup/build
cmake ..
make -j $(nproc) skeleton
Get the installer of your choice, e.g. Unreal Tournament and copy its content to the skeleton direcory:
git clone https://github.com/liflg/unreal.tournament_451-english_x86.git
cp -pr unreal.tournament_451-english_x86/* skeleton/
cd skeleton
./mojosetup