these 3 derivations will be built:
  /nix/store/kn5b7ck7lvvbpg21xpixh03bf4psgcp1-hol_guard-3.6.3.tar.gz.drv
  /nix/store/8p97k6w0jmxqcxgw14s5vyn3hpzwxj5k-hol-guard-3.6.3.drv
  /nix/store/gw9jkgm6iw0p6amrna8clvq32f5j7izc-check-hol-guard.drv