Silencing MDC Warning with gnupg 2.2.8.

[Ralph Corderoy]

Hi,

With the arrival of gnupg 2.2.8-1 on Arch Linux this command applied to
members of an archive of files on read-only media fails because they old
enough not to have Modification Detection Codes.

    gpg -q --batch --no-mdc-warning -d --passphrase-fd 0 foo.gpg

I see that --ignore-mdc-error downgrades the error to a warning allowing
the decrypted content to appear on stdout, but unfortunately for me
--no-mdc-warning is now a no-op and so doesn't work in concert with
--ignore-mdc-error to silence the warning.

It seems from skimming the source that my only option is to expect and
remove the MDC warning from stderr, allowing the rest of stderr's
content to pass?  Downstream of this command is unhappy otherwise.

gpg(1) still documents --force-mdc and --disable-mdc, saying they're now
no-ops, but --no-mdc-warning is undocumented despite still being
accepted and also a no-op.  This hampers investigating why
--no-mdc-warning isn't working.

BTW, 2.2.8's `NEWS' has `--no-mdc-warn', but the option ends in
`warning' and so my searches didn't find the news item.

-- 
Cheers, Ralph.
https://plus.google.com/+RalphCorderoy