these 2 derivations will be built:
  /nix/store/jgfs7rgh3pm0qx3s6k3lj1dc9wks6vry-harmonia-deps-3.3.0.drv
  /nix/store/yqmna5sgj2insi74jhrqp10qd37l59fb-harmonia-llvm-cov-3.3.0.drv