id-Software/Quake-III-Arena ? reverse-engineered prompt

I want you to turn this Quake III Arena GPL source release into something I can actually build and run on a modern computer without fighting old compiler issues. Keep the original game behavior and feel intact, but clean up whatever is needed so it builds reliably on current Windows, Linux, and Mac setups if that is practical from the source here. Please wire up an easy build flow, fix obvious portability problems, and leave clear instructions for how to compile and launch the game.

If the extra tools in here like the map compiler or editor can be built too, great, but the main priority is getting the core game source working first. I would also like any small quality of life improvements that help with modern environments, as long as they do not change the actual gameplay. Add notes about anything that still depends on original game data or has licensing limits. You can look up current docs or community build guidance online if needed, but keep the result self contained and easy to use.