these 2 derivations will be built:
  /nix/store/s1m565fr34gmjvvml4x3lk4r0ja981bj-harmonia-deps-3.3.0.drv
  /nix/store/bfphbr1nighaddabrkx5nxdfsia2dwvw-harmonia-llvm-cov-3.3.0.drv