these 3 derivations will be built:
  /nix/store/rk6q6drbp0pqkpf8vvhzrihirf6fnfmv-source.drv
  /nix/store/w4hsvjiijl4gkmj08hvzcrxls1f8avmi-mcptoon-0.8.12.drv
  /nix/store/8wy1nyhpkwmn0vnvjy92axd91mfb8yhg-check-mcptoon.drv