[Distutils] make-like develop

[Andrea Crotti]

Supposing that we have a directory with many eggs that compose our 
framework.

All these eggs  might (or might not be) used by applications that we write.
So at the moment we run "python setup.py develop" on all of them.

To avoid to waste too much time, however, the builder does a make-like
operation, checking if "setup.py" was modified.

So since I'm rewriting a new system to build/develop:
- does it make sense to re-run develop when setup.py changes.
   And if yes are there other possible conditions which would force me 
to re-run it?

- what could be a good way to implement a similar mechanism?
   Is there anything already I could use?

I've seen watchdog (http://pypi.python.org/pypi/watchdog) which looks 
very interesting,
and might be good to implement a service, but maybe it's overkill...