* mail/rmail.el (rmail-enable-mime-composing): New. A lightweight
version of rmail-enable-mime.
(rmail-forward): Use it.
* message.el (message-forward-rmail-make-body):
save-window-excursion.
(message-encode-message-body): no error.
(message-setup-1): compose-mail send-actions are different from
message-send-actions.
* message.el (message-forward-subject-author-subject): Don't use
message-news-p, which widens the buffer.
(message-forward-make-body): New function.
(message-forward): Use it.
(message-insinuate-rmail): New.
(message-forward-rmail-make-body): New.