these 4 derivations will be built:
  /nix/store/xyjhdmklah5ga2qvlqg8fzmkqycmxbiq-omp-18.12.3-cargo-vendor-vendor-staging.drv
  /nix/store/190m8kic3w3v6dj3m71d365qjhpww67m-omp-18.12.3-cargo-vendor-vendor.drv
  /nix/store/jm8rp6wgsbdhp587kdcf5sl6xn3q6akw-omp-18.12.3.drv
  /nix/store/rfxacvs03ncrm6q0f25r21955sb3i3hk-check-omp.drv