these 2 derivations will be built:
  /nix/store/1mkvx3qz6am6p0y06mvxqgspqxpx4zgx-herdr-0.9.1-vendor.drv
  /nix/store/jz4vxvsw2nm0spil4w5vdkki5h7v916w-herdr-0.9.1.drv