Just wanted to pop in here, I have a makefile working for linux: https://github.com/gwx/ZeldaClassic/tree/active.
I completely tore up the old makefile in trying to get it to work, so it's not recognizably the same. It also lets you switch between allegro 4.2 and allegro 4.4, and has a few other switches set up to turn debug symbols off/on, etc.
I've been trying to schedule some time on a windows machine so I can get it working for windows as well.