these 2 derivations will be built:
  /nix/store/l5h36yk5b11mar8456vrcrxx3i1vv3l4-mardi-gras-0.34.0.drv
  /nix/store/fsx2rn0xl7dy2l28s3py6i7n0i7xkrdv-check-mardi-gras.drv