postgresql-8.3RC2 and the continuing saga of libreadline

I have a special requirement which I am told is addressed with string
arrays in the upcoming release, where I will be able to establish, for
example 192 nulls within a string.

Downloaded the tarball for 8.3RC2 with great expectations earlier today
and stumbled into the murky waters of readline location. This problem
seems to have come up over the past 5 years. The solution is almost
always the same, although I have never understood why it is here in the
first place.

In my Mandriva 2008.1, libreadline files are placed by the binary
distribution this way:
/lib/libreadline.so.5
/lib/libreadline.so
/lib/libreadline.so.5.2
/usr/lib/libreadline.so
/usr/lib/libreadline.a
and: /usr/share/doc/libreadline5-devel.

The usual posted 'fix' is to help postgres find what it wants by using
the --with-libs directive.

Okay, so I tried both --with-libs=/lib and --with-libs=/usr/lib to no
avail.

Is there something I can do to assuage this tarball's appetite???