[Dovecot] dovecot: auth(default): Fatal: Unknown database driver 'mysql'

[Glen Lee Edwards]

I just tried upgrading from 1.1.rc6 to v1.2.11, and am getting the 
following error:
dovecot: auth(default): Fatal: Unknown database driver 'mysql'. 
If I change the respective line in dovecot-sql.conf from driver = mysql to
driver = pgsql the error message changes accordingly:
dovecot: auth(default): Fatal: Unknown database driver 'pgsql'.

I quit using 1.1.rc6 because it started choking on my Debian system, so 
I'm back
to using the stable Debian version - 1:1.0.15-2.3+lenny1.  Where are the 
drivers kept
when I do a default build, and where in the configuration file does it 
tell dovecot to
look for the drivers?  Other suggestions on a fix?

Glen