This is an unfinished patch to handle Dovecot locking, which is useful
if we'd like to support running notmuch directly on a Dovecot Maildir:

  http://wiki.dovecot.org/MailboxFormat/Maildir#Locking

For now, I'm interested in general comments, i.e. is this desirable, is
it a reasonable approach, etc.  As you can see, there's no config
handling yet, so -llockfile is added unconditionally.

-- 
Rob Browning
rlb @defaultvalue.org and @debian.org
GPG as of 2002-11-03 14DD 432F AE39 534D B592 F9A0 25C8 D377 8C7E 73A4