`mail-encode-header' encodes encoded header

[Katsumi Yamaoka]

Hi,

2012-03-10  Richard Stallman  <address@hidden>

        * mail/sendmail.el (mail-encode-header):
        Set rfc2047-encode-encoded-words.

Please don't do that.  Because:

2011-05-27  Kenichi Handa  <address@hidden>

        * mail/sendmail.el (mail-encode-header): Avoid double encoding by
        let-binding rfc2047-encode-encoded-words to nil.

I use Gnus and smtpmail, that uses mail-encode-header, to send
mails.  Gnus passes a mail of which the header and the body are
fully encoded to smtpmail, so the double encoding takes place!
I often write mail's subject in Japanese, Gnus encodes it into

Subject: =?iso-2022-jp?B?GyRCJUYlOSVIGyhC?=

, and now it is encoded again into:

Subject: =?us-ascii?Q?=3D=3Fiso-2022-jp=3FB=3FGyRCJUYlOSVIGyhC=3F=3D?=

There is no mail software that decodes it into human-readable one.

Regards,