these 2 derivations will be built:
  /nix/store/8d5dpkayprm7h1vway2fg95r6i4zllfj-lean-ctx-3.10.0-vendor.drv
  /nix/store/a2ayx1880d1r5gah6ad6k5221w7qg93p-lean-ctx-3.10.0.drv