* gnus-group.el (gnus-safe-html-newsgroups): New user option.

* gnus-group.el (gnus-safe-html-newsgroups): New user option.

* gnus-art.el (gnus-bind-safe-url-regexp): New macro.
(gnus-mime-view-all-parts, gnus-mime-view-part-internally)
(gnus-mm-display-part, gnus-mime-display-single)
(gnus-mime-display-alternative): Use gnus-bind-safe-url-regexp to
override mm-w3m-safe-url-regexp according to gnus-safe-html-newsgroups.

* gnus-sum.el
(gnus-mark-copied-or-moved-articles-as-expirable): New user option.
(gnus-summary-move-article): Add expirable mark to articles copied or
moved to group that has auto-expire turned on if the option is non-nil.