these 4 derivations will be built:
  /nix/store/m4fqby555sfha4i5j5jspjqj750yj269-nix-tarmac-0.1.0.drv
  /nix/store/rc9xb58109bqp4aiaa2b04fjhjcw6jq9-nix-tarmac-0.1.0.drv
  /nix/store/w3xl3vf8528hk000kcngz5zy3zkx9ill-nix-tarmac-0.1.0.drv
  /nix/store/6k2dcjjb6ipbg5641si6qc90n2rkdnd1-nix-tarmac-dispatcher.drv