Pull request (mdw/powm-sec): Use GMP constant-time modexp

[Ian Jackson]

In article <87lgwiz549.fsf.mdw at gibson.dhcp.distorted.org.uk>,
Mark Wooding  <mdw at distorted.org.uk> wrote:
> The following changes since commit 11653375c39594d5d4822498941bc6288d0136ed:
>   Finalise 0.4.0 (2015-02-28 15:26:03 +0000)
> are available in the git repository at:
>   https://git.distorted.org.uk/~mdw/secnet/ mdw/powm-sec
> for you to fetch changes up to b6aae8b2364f24edc13c6cdf774bb8c8d282e02f:
>   dh.c, rsa.c: use `mpz_powm_sec' for modexps. (2016-09-29 00:47:03 +0100)

Merged, thanks.

Ian.