configure --with-xxxx problem

I notice configure from 6.5 cvs doesn't checks anything after --with
option. First time I run
./configure --with-port=5433 
and was very surprised when postmaster doesn't want to start with port=5433
after compilation and installation. Configure doesn't complaints !!!
It takes some time when I realized I had to 
./configure --with-pgport=5433

Also,  you can specify any option begins from --with-
configure will not complain about unknown option, just silently ignore it.
Regards,
    Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83