these 2 derivations will be built:
  /nix/store/yac9rcc9avnpgi8yb08p0g1b7gkyxf5z-hol-guard-3.4.2.drv
  /nix/store/dn5pjfak5akrhxqm8jr91nn5vsnbv82p-check-hol-guard.drv