these 2 derivations will be built:
  /nix/store/by6wd9adb54il3ai7dqll87jmi5y9i5n-harmonia-deps-3.3.0.drv
  /nix/store/6i6fmmqyg0k4khvxmf5f3s5x89w9dx9v-harmonia-llvm-cov-3.3.0.drv