On the POSTGRES= side of things, for an RPM installation you use the magic POSTGRES=LSB incantation.
The nspostgres module Makefile is written to be compiled under the source tree; put it in, using your example, /usr/local/src/aolserver-4.0.9/nspostgres should contain the nspostgres files. INST= is where the *binaries* are installed.
