Install ruby-postgres binding with postgres 8.1

[Pat Maddox]

I want to install the ruby-postgres binding
(ports/databases/ruby-postgres), and I've got postgres 8.1 installed
on my machine.  When I do 'make install', it starts to download
postgresql-client-7.4.9, and then fails because that conflicts with
postgresql-client-8.1.0, which I have installed.  I'd like to somehow
remove the dependency on 7.4.9 and compile against 8.1.0...how can I
do this?

Thanks,
Pat