these 2 derivations will be built:
  /nix/store/na8m2aiq05d3mwic1aqf7haazihbh6gc-harmonia-deps-3.3.0.drv
  /nix/store/bk9xn7hnglhiaqapgydkrpzh168jqrv7-harmonia-llvm-cov-3.3.0.drv