ProFTPD:Mod_auth and AuthPAM problem

i,

I always used ProFTPd without SQL authentication, but would now like to
use it. I'm running ProFTPd in standalone mode.

I compiled ProFTPd 1.2.9 with --with-modules=mod_sql:mod_sql_mysql

Before even starting to implement the MySQL functions, I would like to
keep the PAM authentication I always used.


I added the line

AuthPAM on to my config file and got the message

- Fatal: unknown configuration directive 'AuthPAM' on line 35 of
'/usr/......./proftpd.conf'.

When I changed to compile config command to
--with-modules=mod_auth:mod_sql:mod_sql_mysql

I got the following message when I tried "make"

modules/mod_auth.o(.data+0x260): multiple definition of `auth_module'
modules/mod_auth.o(.data+0x260): first defined here collect2: ld returned
1 exit status make: *** [proftpd] Error 1


What am I missing in the piles of docs?

Thanks

Nico