these 2 derivations will be built:
  /nix/store/xqvqm46v6d3b20xcf6hzjmg9xm1zf6vx-freebuff-0.2.34.drv
  /nix/store/2zqx9b5fb5m5nzvhjvavnl61hqwgihn6-check-freebuff.drv