these 2 derivations will be built:
  /nix/store/nwagn93kdak410s3y6w6vc7z2qn0fa7x-harmonia-deps-3.3.0.drv
  /nix/store/7z92jkshv9cz6pcibp76wrwclafy7xly-harmonia-llvm-cov-3.3.0.drv