these 4 derivations will be built:
  /nix/store/jdhca9n400mqinb7y98vrhzykdlx1kx3-nix-tarmac-0.1.0.drv
  /nix/store/kijqnx94qs9j7ww4b5ah0pj3yk1l9k18-nix-tarmac-0.1.0.drv
  /nix/store/yv6d7vifyd9lp9n27nqmnsl5z9h309dl-nix-tarmac-0.1.0.drv
  /nix/store/d1q4b0j91v2kimsv26wn4lr6fniadwmp-nix-tarmac-dispatcher.drv