[Improve non-ASCII newsgroup names handling]

[Improve non-ASCII newsgroup names handling]

* gnus-agent.el (gnus-agent-rename-group, gnus-agent-delete-group)
(gnus-agent-fetch-articles, gnus-agent-unfetch-articles)
(gnus-agent-crosspost, gnus-agent-backup-overview-buffer)
(gnus-agent-flush-group, gnus-agent-flush-cache)
(gnus-agent-fetch-headers, gnus-agent-load-alist)
(gnus-agent-read-agentview, gnus-agent-expire-group-1)
(gnus-agent-retrieve-headers, gnus-agent-request-article)
(gnus-agent-regenerate-group)
(gnus-agent-update-files-total-fetched-for)
(gnus-agent-update-view-total-fetched-for): Bind
file-name-coding-system to nnmail-pathname-coding-system.
(gnus-agent-group-pathname): Don't encode file names by
nnmail-pathname-coding-system.
(gnus-agent-save-local): Bind file-name-coding-system correctly; bind
coding-system-for-write instead of buffer-file-coding-system to
gnus-agent-file-coding-system.

* gnus-msg.el (gnus-inews-make-draft, gnus-inews-insert-archive-gcc):
Decode group name.

* gnus-srvr.el (gnus-browse-foreign-server): Make group names unibyte.

* gnus-start.el (gnus-update-active-hashtb-from-killed)
(gnus-read-newsrc-el-file): Make group names unibyte.

* nnmail.el (nnmail-group-pathname): Don't encode file names by
nnmail-pathname-coding-system.

* nnrss.el (nnrss-file-coding-system): Doc fix; make it begin with *.
(nnrss-request-delete-group): Bind file-name-coding-system to
nnmail-pathname-coding-system.
(nnrss-read-server-data, nnrss-read-group-data): Bind
file-name-coding-system correctly.
(nnrss-check-group): Pass nnrss-file-coding-system to md5.

* nntp.el: Require gnus-group for the function gnus-group-name-charset.
(nntp-server-to-method-cache): New variable.
(nntp-group-pathname): New function that decodes non-ASCII group names.
(nntp-possibly-create-directory, nntp-marks-changed-p)
(nntp-save-marks, nntp-open-marks): Use it.
(nntp-possibly-create-directory, nntp-open-marks):
Bind file-name-coding-system to nnmail-pathname-coding-system.
(nntp-open-marks): Decode group names when bootstrapping marks.

* rfc2047.el (rfc2047-encode-message-header): Make XEmacs decode
Newsgroups and Folowup-To headers.