Patch: make AbstractGraphicsState.clone public

[Alexandre Petit-Bianco]

Bryce McKinlay writes:

> If the compiler bug is fixed on the branch (which it should be),
> then presumably this patch needs to go on the branch as well?

The compiler bug isn't fixed in the branch or in the trunk, it's part
of a fairly big patch (that would interact badly with your access
check patch AFAIR) that flew back and force between you, Tom and
myself a month or so ago. I'm actually tying loose ends, this is one
of the things I want to commit to the trunk, not necessarily the
branch.

./A