[texdoc] nonstandard arg parsing

[Karl Berry]

    unless the LuaTeX devs decide to include it.

>From everything I have heard, I think that is well outside anything
Roberto wants to add to the Lua core.

    didn't event know that POSIX said anything about command-line options)

Yes, and it specifies that -iw generally means -i -w :).

What POSIX doesn't say anything about are --long-options.

     (I really don't think we need something as big as Perl's
     Getopt::Long, do we?)

Getopt::Long has many options and features we don't need.  But we need
the basic functionality of the original GNU getopt_long.

I certainly agree with Reinhard that it's not a trivial project to
implement a getopt_long in pure Lua.  But that is what is needed.  If
someone else has written it, great.  If not, seems like it should not be
*that* hard.  Of course, all of us are already so overloaded ...

Thanks,
karl