If fixing things in this makefile is not your job, then it really is amazing.

Honestly its like any other tool we use: once you know the rules governing its behavior it really isn't that hard to debug issues. Make is very consistent in most cases. There are plenty of traps, and they're made easier to fall into given the archaic syntax, but you don't typically have to fall into them over and over again :).

Yes but some tools have... shall we say, irregular rules. Tell me how CMake's argument quoting works for example.

Actually, you might want to glance at the first few hundred lines of platform specific stuff you are supposed to set manually before the main makefile begins. Literally meant to be set by hand, but the Git developers made educated guesses about the specifics of each platform.