I think it belongs on superuser or stackoverflow. LilyPond - how to write a basic makefile
Good question. Makefiles per se would be off topic. I think in this case it's clearly relevant to writing scores using LilyPond or command line tools for ABC like abc2ps or abcm2ps. But it is a stretch and we shouldn't open the door to all technology related to these tools.
"What OS to choose for LilyPond?", "Which shell for running LilyPond?" -- these would clearly be over the line.