How to syncronize build environments

[John Seghers]

We have multiple people working at multiple sites with the openmoko
environment.  For our internal usage we've got overlays of things like
the dialer.

To try and minimize churn, we don't do a "make update" too frequently,
and when we do, we would like one person to do so, and do any merging of
external changes into our overlays and then have the other people
update.

So my question is: How do we synchronize the openmoko environment when
there may be a week or two difference between when one person pulls the
update and when another one does?

Thanks,

- John