Here's how to compile klystrack. You need both the klystrack project and the klystron project (which provides the synth and graphical routines):

    git clone --recurse-submodules https://github.com/kometbomb/klystrack.git

klystron is included as a Git submodule and the above commands will clone that as well. To build the actual binaries.

    cd klystrack
    make

You now have the main executable in klystrack/bin.debug

The theme files you also need are in klystrack/res after the make. Depending on the build settings, the res directory has to be copied where the executable is or in /usr/lib/klystrack. On Windows, the first is the default. On Linux, the latter. The keymap directory goes next to the res directory.

You of course also need the suitable SDL2 and SDL2_image development libraries.