Marking a port as broken

[Adam Mercer]

Hi

I have some ports that are out of date due to the newer versions no
longer building on macOS and the latest version of dependencies no
longer supporting the older versions that still support macOS. I'm
working with upstream to try and resolve this but in the meantime is
there a way to mark these ports as broken and return a note when
trying to build them?

Cheers

Adam