[Dovecot] Strange directory created at dovecot launch

[Eric]

I installed dovecot from scratch and compiled it from 1.0.0 source.
Installed in /usr/local.
Now everytime I launch dovecot it creates and uses
/usr/local/var/lib/dovecot and /usr/local/var/run/dovecot directories. For
the latter I found the modifications to do in dovecot.conf for using
/var/run/dovecot instead, but for the former I see nothing about such
directory in dovecot.conf. What happens ? How can I configure it so that
dovecot uses /var/lib/dovecot instead ?

Thank you

Eric