these 2 derivations will be built:
  /nix/store/4qcg3vh8y4qgdqfsk4sysh3wihicvvah-herdr-0.9.1-vendor.drv
  /nix/store/g8b94yfjgx27yg4pkzcyjgn4zqbiqwhh-herdr-0.9.1.drv