ocaml-configurator fails to build: Error: I cannot find the root of the current workspace/project

[barracuda156]

--->  Extracting configurator-0.11.0.tar.gz
Executing:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_ocaml_ocaml-configurator/ocaml-configurator/work" && /usr/bin/gzip -dc '/opt/local/var/macports/distfiles/ocaml-configurator/configurator-0.11.0.tar.gz' | /usr/bin/gnutar --no-same-owner -xf - 
--->  Configuring ocaml-configurator
--->  Building ocaml-configurator
Error: I cannot find the root of the current workspace/project.
If you would like to create a new dune project, you can type:

    dune init project NAME

Otherwise, please make sure to run dune inside an existing project or
workspace. For more information about how dune identifies the root of the
current workspace/project, please refer to
https://dune.readthedocs.io/en/stable/usage.html#finding-the-root
Command failed: /opt/local/bin/dune upgrade
Exit code: 1