Update to GCC copyright assignment policy

[Maciej W. Rozycki]

On Tue, 1 Jun 2021, Paul Koning via Gcc wrote:

> That seems to create a possible future complication.  Prior to this 
> change, the FSF (as owner of the copyright) could make changes such as 
> replacing the GPL 2 license by GPL 3.  With the policy change, that 
> would no longer be possible, unless you get the approval of all the 
> copyright holders.  This may not be considered a problem, but it does 
> seem like a change.

 It is a real problem.  As I recall a while ago parts of QEMU had to be 
removed and reimplemented from scratch when the project switched licences, 
because a contributor and therefore a copyright holder (whom I knew in 
person and who I am sure would make no fuss about it) has since passed 
away.

  Maciej