Error when building postgresql with contrib functions

Hi

I am trying to build postgresql with contrib functions from source code
checked out from cvs version 8.3.8 but getting error:

==================
conifer=# SELECT * FROM xpath_table('id', 't', 'xpath_test', '/doc/int',
'true') as t(id int4);
ERROR: function xpath_table(unknown, unknown, unknown, unknown, unknown)
does not exist
LINE 1: SELECT * FROM xpath_table('id', 't', 'xpath_test', '/doc/int...
^
HINT: No function matches the given name and argument types. You might need
to add explicit type casts.
==================

Looks like the contrib functions have not been added in.

OS Ubuntu Karmic.

I checked out source code from branch 8.3.8. Before building postgresql,
$ sudo apt-get install libreadline6-dev zlib1g-dev libxml2-dev libxslt1-dev
bison flex

libreadline6-dev needs libncurses5-dev as dependency so libncurses5-dev was
also installed.

The installation step I performed:
$ ./configure --with-libxml --with-libxslt
$ make
$ make check
$ sudo make install
$ export PGDATA=/data/pgsql/data
$ initdb
$ createdb conifer
$ pg_ctl start
$ psql

everything looks fine but I got error by doing:
================
conifer=# CREATE TABLE xpath_test (id integer NOT NULL, t xml);
CREATE TABLE
conifer=# INSERT INTO xpath_test VALUES (1, '<doc><int>1</int></doc>');
INSERT 0 1
conifer=# SELECT * FROM xpath_table('id', 't', 'xpath_test', '/doc/int',
'true') as t(id int4);
ERROR: function xpath_table(unknown, unknown, unknown, unknown, unknown)
does not exist
LINE 1: SELECT * FROM xpath_table('id', 't', 'xpath_test', '/doc/int...
^
HINT: No function matches the given name and argument types. You might need
to add explicit type casts.
================

Thank you very much for your help.

Best,
M Z