Synch with Gnus trunk.

Synch with Gnus trunk.
* mail/binhex.el (binhex-decode-region-internal)
* mail/uudecode.el (uudecode-decode-region-internal)
* net/dns.el (dns-read-string-name, dns-write, dns-read)
(dns-read-type, dns-query)
* pgg-parse.el (pgg-parse-armor)
* pgg.el (pgg-verify-region)
* sha1.el (sha1-string-external): Don't run set-buffer-multibyte for
XEmacs.

* net/imap.el (imap-disable-multibyte): Redefine them as a macro.

* nnweb.el (nnweb-gmane-search)
* yenc.el (yenc-decode-region): Don't run set-buffer-multibyte for
XEmacs.

* gnus-art.el (gnus-article-browse-html-parts)
* gnus-group.el (gnus-read-ephemeral-gmane-group)
(gnus-read-ephemeral-bug-grou): Use mm-make-temp-file instead of
make-temp-file.

* gnus-dired.el (gnus-dired-mode): Bind gnus-dired-mode-hook,
gnus-dired-mode-on-hook and gnus-dired-mode-off-hook for XEmacs when
compiling.

* gnus-ml.el (gnus-mailing-list-mode): Bind gnus-mailing-list-mode-hook,
gnus-mailing-list-mode-on-hook and gnus-mailing-list-mode-off-hook for
XEmacs when compiling.

* gnus-salt.el (gnus-pick-mode): Bind gnus-pick-mode-on-hook and
gnus-pick-mode-off-hook for XEmacs when compiling.
(gnus-binary-mode): Bind gnus-binary-mode-on-hook and
gnus-binary-mode-off-hook for XEmacs when compiling.

* gnus-sum.el (gnus-summary-limit-strange-charsets-predicate): Return
nil if char-charset is not available.

* sieve-manage.el (sieve-manage-disable-multibyte): Redefine them as a
macro.

* mm-url.el (mm-url-form-encode-xwfu): Use mm-encode-coding-string
instead of encode-coding-string.

* mm-util.el (mm-enable-multibyte, mm-disable-multibyte): Use (featurep
'xemacs) instead of mm-emacs-mule to switch function definitions.
(mm-with-unibyte-current-buffer): Make it a progn macro for XEmacs.