these 3 derivations will be built:
  /nix/store/rxkk1pr79c7kzbdsi126a4b0ga0qkc9f-hol_guard-3.15.0.tar.gz.drv
  /nix/store/6nbq09ifa3pxr1i7ylj5y1gzria7jgqj-hol-guard-3.15.0.drv
  /nix/store/z4qbh3qnxh4xg792551vc3i75djpgx0x-check-hol-guard.drv