these 2 derivations will be built:
  /nix/store/dc1js55pcm9za9nzrnylicxsyz1bblgr-harmonia-deps-3.1.0.drv
  /nix/store/immkczr51by0dhhirafn2nlpwxk8b265-harmonia-llvm-cov-3.1.0.drv