GPL and NDA

[dewar at gnat.com]

<<You say that it can work if you can atomically GPL and distribute it
but that doesn't make any sense to me.  By creating a dervied work
from a GPL work, the new work is GPL'd from the time of its creation.
>>

This sort of claim is just plain wrong. The GPL is a license that the
owner of the copyright provides to another person. If you create a
deriviative work, then this work is covered by the GPL if and only
if you as the creator decide to issue that license.

Of course if you do NOT issue the license, and then distribute the work,
you have violated the original copyright, but it can never be the case 
that something is automatically covered by the GPL.

Furthermore, if you create the deriviative work solely for your own use,
and do not distribute it, then there is absolutely no reason for you to
issue any license to anyone for the deriviative work.