detecting if a Makefile is GNU make-ish

[Alfred M. Szmidt]

Is there some way of detecting or specifying that a Makefile is GNU
make specific?  I'm kinda thinking of something similar to the .POSIX
directive.

I'm in a situation where got a bunch of Makefiles, some BSD makefile,
some GNU, some POSIX and to somehow handle this without having to
remeber if one is to type make, gmake, nmake, I want to create a small
wrapper that can sorta figure it out by itself.

Other ideas are welcome too ...