Building chefdk rpm, apparently with omnibus

I’d like to build a testable RPM for chefdk. But I’m unclear on how to build an RPM from the omnibus in chefdk. Sadly, the documentation is a bit unclear to me. Can anyone point me to the right syntax to build RPM’s from omnibus for chefdk?

I think this is what you are looking for: https://github.com/chef/omnibus/blob/master/docs/Building%20on%20RHEL.md

You will need to build omnibus and then build Chef.
https://github.com/chef/omnibus/blob/master/docs/Building%20on%20RHEL.md

and

https://github.com/chef/chef#building-the-full-package