these 2 derivations will be built:
  /nix/store/mgx5xima6vqvzzq4r5d6i4bn1fh6lg5x-magpie-0.1.660.drv
  /nix/store/9bzw9r4sdczndxfbddfbjxkrxpn9wlxz-check-magpie.drv