Those versions are gone (unless I'm misunderstanding you), everything is msbuild based now. And appears that nmake doesn't even understand the standard make syntax so it doesn't really seem useful here (if a seperate set of files has to be maintained anyway, opting for the type that is used most and also happens to be the most convenient seems a better option).
Another option might be to try to use the current make files by using make from cygwin or mingw, but that won't be easy, nor nice, given that the files are written with gcc and a complete unix shell in mind. Solving that would yield a horrid mess. Which is probably why I don't seem to remember I ever encountered it before.