these 3 derivations will be built:
  /nix/store/731sx2rfs967qi1jldg6f2c0wp749qks-source.drv
  /nix/store/3vb7xdb9xl82jr31im4jk0qr1cq7js2f-mcptoon-0.8.12.drv
  /nix/store/0l259bklglxi247ln7ibmmpw1r7xnq75-check-mcptoon.drv