<hr /><i>ben added on 2011-05-30 16:49:12 UTC:</i><br />
I've committed a Makefile which works on (at least) Mac OS X, Linux, FreeBSD, NetBSD and Solaris.

For the *BSDs and Solaris, it won't work if GNU make is used. However, this is no worse than it was before I messed with it to get it to work under Solaris.