[Dovecot] new configure-option --disable-index

[Marten Lehmann]

Hello,

> As "default_mail_env" is fixed for all users, I'm not understanding why 
> adding ":INDEX=MEMORY" to whereever its read from would be problematic.

I don't have a default_mail_env setting, because there is no default. I 
now tried to set "default_mail_env = INDEX=MEMORY", but this gives me 
the following in the error-log:

Error: pop3(imaptest at test.de): Ambiguous mail location setting, don't 
know what to do with it: INDEX=MEMORY (try prefixing it with mbox: or 
maildir:)
Error: pop3(imaptest at test.de): Failed to create storage with data: 
INDEX=MEMORY

How can I simply set INDEX=MEMORY without defining a default?

Regards
Marten