> Since those makefile includes appear to be BSD'isms, and work just fine
> under NetBSD, I have three questions:
> 
> 1. are those actually in separate makefiles somewhere or are they some
> strange, semi-implicit rules?
> 
> 2. if they're actually makefiles in themselves, is there any reason that I
> couldn't include them as part of a not-for-profit distribution to allow
> compatibility with non-BSD systems?  Are there copyright issues involved?
> 
> 3. are they likely to work under Linux (a semi-BSD system) with GNU make?

I think the problem is basically that (for 4.4 I think) Berkeley
completely re-wrote make, adding a lot of features which other
forms of make lack.

Check for bmake (Berkeley make), which I think GNU or Linux has.

The advantage of the re-write is that a whole lot of make files
shrink tremendously.

Take care,

Bill