> As it happens, a new 1.9.0 version of rbw has just been released - it
> contains the aforementioned fix, as well as some other improvements[0].

Committed, thanks. The ring dependency was updated to 0.17, which has
support for powerpc64 and riscv64 and supports xonly and branch-target
landing pads natively. So I adjusted the NOT_FOR_ARCHS and dropped the
bdep on security/rust-ring.

> -MODCARGO_CRATES +=	ring	0.16.20	# LICENSE
[..]
> +MODCARGO_CRATES +=	ring	0.17.7	# LICENSE