This is Andrew McCallum's <mccallum@jprc.com> modification of Miles
Bader's `argp' functions.

`argp' is a collection of functions in GNU libc 2.x that provides
powerful command-line argument processing and automated usage message
printing.

Andrew McCallum modified it by pulling it out into a separate library,
and removing its dependancies on GNU libc.  The result doesn't produce
usage messages that are nearly as pretty, but at least it compiles on
SunOS and other OS's with inferior libc's.
