Any way to stop PostgreSQL from using Unix domain sockets?

Ok, here's the situation: we need to be able to spin the server running
PostgreSQL down for power reasons (we have it set for wake on lan, so
we'll still pick up the connections). However, the checkpoint code
breaks out of its select every 5 minutes to do its thing. When it
re-enters the select, it apparently "pings" the unix domain socket file
in /tmp, which causes the disk to spin up, which causes the machine to
wake up from power saver.

I know you can set the checkpoint timeout via postgresql.conf, however
the highest setting is 3600 seconds, which isn't good enough (don't
ask). So, alternately, is there any easy way I can configure PostgreSQL
to TCP exclusively (i.e. no unix domain sockets *at all*)?

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