Postgresql 9.0 (pgxs.mk)

Hi,

I have installed Posgresql 9.0 onto my Ubuntu 10.04 system, and runs
perfectly. I installed it via the Ubutu repo (apt-get install). However, I
am trying to get the PgPool working as well. I am trying 'make' one of the
component from the PgPool package, and it returned me this error:-

Makefile:14: /usr/lib/postgresql/9.0/lib/pgxs/src/makefiles/pgxs.mk: No such
file or directory
make: *** No rule to make target
`/usr/lib/postgresql/9.0/lib/pgxs/src/makefiles/pgxs.mk'. Stop.

May I know how can I fix this problem? What should I do, or rather install
in oder to have the pgxs path available onto my system. Not much info on the
net for this issues using Postgresql 9.0

Please assist.

Thanks