Nicholas Bamber has added a lot of functionality to Duende.  Since this
functionality uses the argp library, and since MaraDNS 2.0.03 is a 
bugfix-only release of MaraDNS, I have given this improved Duende the
name "duende-ng.c" in the "tools/" directory.  Most MaraDNS users should
use this improved Duende.

Its new command-line options are documented in the source of duende-ng.c