Add the smtpd module to the list of undocumented modules; Barry needs to

write the documentation for this module.

Doc/lib/libundoc.tex

@@ -45,6 +45,10 @@ Some of these are very old and/or not very robust; marked with ``hmm.''
 
 \item[\module{ihooks}]
 --- Import hook support (for \refmodule{rexec}; may become obsolete).
+
+\item[\module{smtpd}]
+--- An SMTP daemon implementation which meets the minimum requirements
+for \rfc{821} conformance.
 \end{description}