Installing GNU Make is not the problem. It's knowing which Make to invoke. If you use GNUMakefile, it's unambiguous.
Of course the "recursive make considered harmful" paper also articulates pretty well why such a usage may have its own problems. http://aegis.sourceforge.net/auug97.pdf
The solution, like the other people were saying, is to name the makefile as GNUmakefile if it is using GNU Make specific features.
[citation needed] Gnu make is a superset of posix compatible make standard.(with very few exceptions) It shouldn't break. If it breaks, I think it's a bug, and the makefile should be altered into posix-compliant compatibility with gnu make.
>[citation needed]
From OpenBSD make(1) manpage: "The handling of ‘.depend’ is a BSD extension."
Considering it's the default on the OS I'm using to post this (OpenBSD) I'd regard it as fairly standard.
On top of that you want to rewrite all of the Makefiles for other implementations of Make, that exist on systems where the implementation of Make that is included with the system is not GNU Make, so that the system still works after you've switched out the implementation of Make that came with the system with GNU Make.
...
Why?
Why should everyone else do a bunch of extra work just so that the projects using GNU Make can keep using GNU Make specific features, when literally all those people using those GNU Make features had to do was to rename their Makefile to GNUmakefile and it would keep working for them when they invoke GNU Make just the same way they did before and would not cause confusion for others?