[gccgo] Add notes about contributing patches

[Robert Dewar]

On 12/3/2010 3:27 PM, Alexandre Oliva wrote:
> On Dec  3, 2010, Ian Lance Taylor<iant@google.com>  wrote:
>
>> the Google copyright assignment
>
> Please don't call it a copyright assignment.  It isn't one.  It's a
> license agreement.  Using an inappropriate term to describe it was what
> got this discussion started.

That's a VERY important point. I often find that a key element
that people need to understanding "assigning" the copyright to
FSF is that the agreement in no way limits what they you can
do in the future (make future versions proprietary, issue
other licenses for the same version etc).