these 2 derivations will be built:
  /nix/store/4z0ya2ddqpk6j6z739sdxk0kjw34dqr4-harmonia-deps-3.1.0.drv
  /nix/store/g934zb6q4vm764rcls32bip1dzs4la6g-harmonia-llvm-cov-3.1.0.drv