* dgnushack.el: Autoload mail-extract-address-components for XEmacs.
* gnus-art.el: Don't autoload mail-extract-address-components.
* gnus.el: Remove duplicated autoload for message-y-or-n-p; use
eval-and-compile to evaluate it.
* hashcash.el: Don't autoload executable-find.
* nndb.el: Don't declare the nndb back end two or more times; don't
autoload news-reply-mode, news-setup, cancel-timer and telnet.
* nntp.el: Autoload format-spec instead of format; use
eval-and-compile to evaluate autoload forms.