these 2 derivations will be built:
  /nix/store/jrlx21dafn5xwcjr7wz19fl4r0z5s2il-harmonia-deps-3.2.0.drv
  /nix/store/5cjv16vxx6dk7blah338lvw0v9kiv0gc-harmonia-llvm-cov-3.2.0.drv