Problem building Postgis 1.5.x for Pg 8.4 on Ubuntu 9.10

Question

Here are things installed:

$ sudo apt-get install postgresql-server-dev-8.4 libpq5 libpq-dev

Here is a past to my config.out: http://pastebin.com/8Nk6pr96

And, here are some hints I got from IRC (names concealed)

< foo> it's NOT failing to find libpq.
< foo> libpq is present, but not compilable without adding a boatload of other -l flags
< foo> and postgis' configure doesn't let you specify that via LIBS
< foo> his paste contains the config.out, which shows this

The configure dies with this, configure: error: could not find libpq

I intend to install postgis for mapfish :)