maildir supports a 'P' flag which denotes the fact that a message has
been 'passed' on (forwarded, bounced). notmuch syncs this to the
'passed' tag.
Per https://tools.ietf.org/html/rfc5788, IMAP has a user-defined flag
(keyword) '$Forwarded' that is supported by many servers and clients
these days. (Technically, one should check for '$Forwarded' in the
server response.)
Restructure mbsync's flag parser to accept keywords (flags starting with
'$') but still bail out on unknown system flags (flags starting with '\').
Support '$Forwarded' as a first keyword since it maps to maildir's 'P'
and needs to be sorted in between the system flags.
Signed-off-by: Michael J Gruber <github@grubix.eu>
Mailbox driver flags are defined in several places. It is essential that
they are kept in sync, so mark them with the same string for easy
grepping with an alerting boiler plate.
Signed-off-by: Michael J Gruber <github@grubix.eu>
do that by wrapping the actual stores into proxies.
the proxy driver's code is auto-generated from function templates, some
parameters, and the declarations of the driver functions themselves.
attempts to do it with CPP macros turned out to be a nightmare.
