hmmm, I don't know anything about telling it that I'm using AOLserver3. I did get the NSHOME, lib, and include directories right. Those were the only three parameters I changed in the makefile. It did put the driver in the right directory.
Also, I've taken a closer look at postgres.c. It declares the class at the top. It uses Ns_DbAddColumnInfo in Ns_PgGetTableInfo. Finally, it defines the class lower. That's all there is to the c side of things.
It sounds, however, that there's something else to the makefile that I don't know about.