these 4 derivations will be built:
  /nix/store/3ympqhjkd55l986717l64h0dsc9vmn5m-nix-tarmac-0.1.0.drv
  /nix/store/sm6zl4a80aisvn3x58d294cbvxw5ik71-nix-tarmac-0.1.0.drv
  /nix/store/yrz8mdbc71092csl584gmabry77hv8b4-nix-tarmac-0.1.0.drv
  /nix/store/nqxr6xn15xk7kij9vd7y1avxjq0y24i1-nix-tarmac-dispatcher.drv