Sanity checking for ./configure options?

I just discovered that ./configure will happily accept '--with-pgport=' 
(I was actually doing =$PGPORT, and didn't realize $PGPORT was empty). 
What you end up with is a compile error in guc.c, with no idea why it's 
broken. Any reason not to have configure or at least make puke if pgport 
isn't valid?
-- 
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com