these 2 derivations will be built:
  /nix/store/gj9r0pm4aw6yah7vc1rwqzi87m2bzl9m-harmonia-deps-3.2.0.drv
  /nix/store/iq99z8fmxaddinjdfzh5rq7i0s9xk5xh-harmonia-llvm-cov-3.2.0.drv