these 2 derivations will be built:
  /nix/store/zwy2hm0hs6hfpg3r3q96rdh3jy5vbbmj-omp-18.10.0.drv
  /nix/store/g3f0nfc6n3x0wcyh1flx85lw59m8c2hq-check-omp.drv