these 2 derivations will be built:
  /nix/store/7qxj0fja7dhnsvygn7qvgm6bbx6rcm8h-nix-tarmac-0.1.0.drv
  /nix/store/3073a6vynzibwjymcky0i0vgxfbw6n58-nix-tarmac-dispatcher.drv