Here's the canonical reference on BSD make: <a href="http://www.freebsd.org/doc/en/books/pmake/index.html" rel="nofollow">http://www.freebsd.org/doc/en/books/pmake/index.html</a>
And if you really want to do cool things with make: <a href="http://www.lulu.com/content/2584447" rel="nofollow">http://www.lulu.com/content/2584447</a>