Hello all,

I've recently set up my mail in Emacs, and it works well. Gmail, though,
doesn't support [1] format=flowed, resulting in the hard-to-read comb
effect when viewing on mobile, which I'd like to avoid. Doing some more
research, I see that the quoted-printable encoding (which Gmail does
support [2], and I've confirmed) can also be used to avoid hard line
breaks while keeping under the line length limit.

Now, I'd like to configure Emacs to send mail using this encoding. To
test this I overwrite `sendmail-program` to log what Emacs sends.
Reading the message-mode and Emacs MIME manuals, I tried setting the
following variables:

(setq
 mm-content-transfer-encoding-defaults
 '((".*" quoted-printable))
 mm-body-charset-encoding-alist
 '((iso-8859-1 . quoted-printable)
   (utf-8      . quoted-printable))
 mm-use-ultra-safe-encoding t)

When sending, no encoding to quoted-printable is done (and there's no
Content-Transfer-Encoding header). To try to debug this further,
inserted the following into a buffer and ran M-: (mml-to-mime)