these 3 derivations will be built:
  /nix/store/cswm9vff9dpsz5c31sb34ch0khxhnhvn-omp-18.12.4-cargo-vendor-vendor.drv
  /nix/store/g1mb34sdh9snjxgd8jfbsdyqm05hygy5-omp-18.12.4.drv
  /nix/store/5xnh48diaj2fp2qwrmnqngp44az5nbn4-check-omp.drv