these 3 derivations will be built:
  /nix/store/xaa4szpyhkic4ymqrkyx1n7drszs7aga-source.drv
  /nix/store/9wvw3g7bm6z975dcablp7inc1kcg6wnz-mcptoon-0.8.40.drv
  /nix/store/all4jj06rzchkkbii68drm3r8774cga3-check-mcptoon.drv