macOS is now a supported system for the Review Board installer. It's

been tested on macOS Ventura and Sonoma. Installation requires the

Command Line Developer Tools and Homebrew to install, but then takes

care of installing everything else needed for a full deployment.
The README has been updated to list the supported versions, and to

separate them out from the supported Linux distros.
As part of this, there's a fix for the check for brew. It no longer

outright crashes if not found.
Unit tests have been added for macOS install steps, and a silly variable

name swap was corrected. The testing datasets for x86 and arm64 had

swapped variable names. The testing results were correct, but all names

were wrong. They've now been corrected.

Unit tests passed.
Tested installing on brand-new macOS Ventura and Sonoma VMs.