these 3 derivations will be built:
  /nix/store/1my4pcjy5p38y35m6wxpkx1ym30y4m7g-hol_guard-3.18.0.tar.gz.drv
  /nix/store/rj53lxhcwncdq8w7v9xlkmy4kkngk8yb-hol-guard-3.18.0.drv
  /nix/store/3lgxc04y7z0g5l4471fcfxz1qkqw5m5z-check-hol-guard.drv