BUG #2138: Feature request: handle foreign key constraints on arrays

The following bug has been logged online:

Bug reference:      2138
Logged by:          Bernhard Rosenkraenzer
Email address:      bero@arklinux.org
PostgreSQL version: 8.1.1
Operating system:   Linux (Ark Linux 2005.2)
Description:        Feature request: handle foreign key constraints on
arrays
Details:

Best illustrated by an example:

A company has several offices and some employees who work in office #1 some
of the time, and in office #2 at a different time.

It would be nice to represent them in the database like this:
CREATE TABLE offices(id SERIAL8 UNIQUE PRIMARY KEY, street VARCHAR(128));
CREATE TABLE employees(id SERIAL8 UNIQUE PRIMARY KEY, name VARCHAR(128),
workplace BIGINT[] REFERENCES offices(id) ON UPDATE CASCADE);

Currently postgres refuses to do this because BIGINT[] and BIGINT are
different types, it would be nice to simply apply the constraint to all
entries in the array if a constraint for type X is applied to X[].