these 2 derivations will be built:
  /nix/store/sqq94vnjbqgv5424sp6qrra7hil0zkna-unreal-agent-0.3.1.drv
  /nix/store/hw9a14vbmgfz0p3kzpz0qbihdlgz0hlp-check-unreal-agent.drv