these 2 derivations will be built:
  /nix/store/i2gvi2xvvhkic5lda7c1z8qqmj8xiqrz-omp-18.3.0.drv
  /nix/store/ywfxpbb0i8xmb2h05hy5a9iir1gsw31p-check-omp.drv