[Dovecot] LDAP authenticated bind support

[J.M. Maurer]

> > Great, thanks. I hate maintaining patches :)
> 
> I actually ended up changing things quite a lot, not just your patch but
> other parts of LDAP code too. It compiles, but I didn't try if it still
> works. :)

Sounds familiar :D

> One thing that I know I changed was checking how bind failures are
> handled. I wanted to separate the invalid password and internal errors.
> Is checking LDAP_INVALID_CREDENTIALS enough? Maybe
> LDAP_INAPPROPRIATE_AUTH or LDAP_INSUFFICIENT_ACCESS?

You mean you want to report an internal error when the ldap_bind
result != (LDAP_INVALID_CREDENTIALS | LDAP_INAPPROPRIATE_AUTH |
LDAP_INSUFFICIENT_ACCESS) ?

I think that that would suffice for most (all?) cases, yes.

Cheers,
  Marc