Update to GCC copyright assignment policy

[Paul Smith]

On Tue, 2021-06-01 at 11:50 -0400, David Edelsohn via Gcc wrote:
> The current, active license in GPL v3.0.  This is not an announcement
> of any change in license.
> 
> Quoting Jason Merrill:
> 
> "GCC's license is "GPL version 3 or later", so if there ever needed
> to be a GPL v4, we could move to it without needing permission from
> anyone."

It depends on what you mean by "move to it".

It's true that anyone could redistribute it under GPLv4.

What's not true is that you can *change the license*.  For example you
can't change the current wording of the license from "GPL version 3 or
later" to "GPL version 4 or later".  Or make any other changes to the
license, without collecting approval from all copyright holders.

So, if there should be some issue with GPLv3 so that you really want to
stop using it (maybe a court case is decided which negates a
significant element of GPLv3 and GPLv4 is released to address the
issue), it won't be possible to do that easily.

Someone else mentioned that new code could be released only under that
license so that in effect the entirety of the codebase becomes GPLv4+.

I'm not sure about that.  Doing that for brand new files that were
created solely by one person who wanted to use GPLv4 or later only
would work I suppose.  But adding changes to an existing file that was
GPLv3+ and saying that these new changes are GPLv4+ would be pretty
gross.  You might have to list both licenses in these files, since you
can't change the previously-in-use license unless you get agreement
from the FSF, who currently holds the license, plus anyone else who
changed the file since the assignment was relaxed.

Personally I think that while assignment is a PITA and I wish it were
easier, it is extremely valuable and provides a lot of flexibility, and
shouldn't be abandoned without very, VERY careful consideration.

And, that decision and those considerations should be documented and
the responses to the issues raised here published for everyone to see.