While working on debugging the VM package, I hit what I believe is a bug
in Emacs itself. To reproduce the problem, run the following steps.

1. emacs -Q
2. C-x b a <return>
3. C-x i b u g b r e v <return>
4. M-x m a i l - s e n d <return>

I attach the "bugbrev" file used above. (It is a very stripped down
version of a spam I got and tried to forward to Spamcop.)

What happens is I get the error message

  mml-to-mime: Symbol’s function definition is void: message-narrow-to-headers-or-head

My elisp skills are quite limited, but from what I understand, this is
triggered by the very long line in the forwarded message, which causes
mail-send to call mml-to-mime. The latter calls
message-narrow-to-headers-or-head but that is not available in this
situation. Shoudn't there be an autoload of that function too?

    (autoload 'message-narrow-to-headers-or-head "message")