these 2 derivations will be built:
  /nix/store/xczxww77dggjykw8w2j6f0jzcrssxfjy-hol-guard-3.16.5.drv
  /nix/store/2fjzaa1kzl5ahysk2bnwlj3ilckwsjcq-check-hol-guard.drv