these 2 derivations will be built:
  /nix/store/02cln2gj0a61bc0a3zmf5a7g5iab3pmp-harmonia-deps-3.1.0.drv
  /nix/store/53fp73nbhns8ncj2wzljcgr0pgzfynfj-harmonia-llvm-cov-3.1.0.drv