these 2 derivations will be built:
  /nix/store/vd6v2b11r3ix6x6vlhrgksk5gpd9y3gj-iets-0.1.0.drv
  /nix/store/1a3w6g40n8x23m0620ygvlh84fsx5a82-iets-diff-e2e.drv