[PATCH 0/2] nptl: Update struct pthread_unwind_buf

[Florian Weimer]

* H. J. Lu:

> libpthread cancellation implementation passes cancel_jmp_buf to
> libgcc unwinder,

Oh.  Where does it do that?  If you mean _Unwind_ForcedUnwind, I think
that's just an opaque closure argument for the callback.