Install pdfroff on macOS
It is recommend to install groff from Homebrew.

Apple's built-in groff is pretty outdated (version 1.19.2) and doesn't include pdfroff.

Homebrew's supplied version on the other hand is up-to-date with recent version available (version 1.22.3).

Install the required packages (GNU troff and Ghostscript) by running:

brew install groff gs