[Dovecot] Trying to building a customized auth plugin

I'm on dovecot 2.0.7 and I trying to building a customized auth plugin.

I take passdb-passwd-file.c and userdb-passwd-file.c to try to build with a simple gcc comand out of dovecot environment as in example:

export DOVECOT=/path/to/untar/dovecot-2.0.7 gcc -fPIC -shared -g -Wall -I$DOVECOT
-I$DOVECOT/src/lib
-I$DOVECOT/src/lib-auth
-I$DOVECOT/src/lib-sql
-I$DOVECOT/src/lib-settings
-I$DOVECOT/src/lib-ntlm
-I$DOVECOT/src/lib-master
-I$DOVECOT/src/auth
passdb-passwd-file.c -o passdb-passwd-file.o

With this, I get errors relate with uoff_t

Is possible to build this plugin by this way?

Another way is patching against one plugin on dovecot RPM, but I prefer this on a separated RPM.