Emacs removes whitespaces at the end of lines

[F. Unglaub]

Hello,

I use emacs with mutt and slrn (post-mode) and noticed that
whitespaces at the end of lines are auto-removed. This leads to
problems, for example, with the signature delimiter "-- \n". In my
case it's reduced to "--\n" which certain newsreaders like tin
consider wrong.

Also those unused headers should have the trailing whitespace IIRC
(for example Summary, Keywords etc.).

Is there any setting that can circumvent this issue?

Regards.
--
"... the Mayo Clinic, named after its founder, Dr. Ted Clinic ..."
                -- Dave Barry