these 2 derivations will be built:
  /nix/store/cbifnp5s9fzc0a85pyzgl7hqgmzw6fkp-iets-0.1.0.drv
  /nix/store/1z3wv5clc07gb6696m3pv8d8nrc2ka8a-iets-diff-e2e.drv