[cairo] [PATCH] fix bugs 15797 (1.8) and 18632 (master)

[Paolo Bonzini]

> The reason why cairo-gstate.c does not do the stack-copy is that it
> incurs significant overhead on renderbench versus plain XRender (and the
> heap copy that snuck into 1.6 was even more painful for all work loads).
> If you have any doubts over the lifetime, just make the copy and only
> worry about if it ever appears on a profile.

No, I don't think there are any doubt over the lifetime, especially if
it is pointed out in a comment.

Thanks for the explanation,

Paolo