Log Message:
nettle: updated to 3.8.1

Nettle 3.8.1 release

This is a bugfix release, fixing a few portability issues
reported for Nettle-3.8.

Bug fixes:

* Avoid non-posix m4 argument references in the chacha
  implementation for arm64, powerpc64 and s390x. Reported by
  Christian Weisgerber, fix contributed by Mamone Tarsha.

* Use explicit .machine pseudo-ops where needed in s390x
  assembly files. Bug report by Andreas K. Huettel, fix
  contributed by Mamone Tarsha.

Optimizations:

* Implemented runtime detection of cpu features for OpenBSD on
  arm64. Contributed by Christian Weisgerber.

The new version is intended to be fully source and binary
compatible with Nettle-3.6. The shared library names are
libnettle.so.8.6 and libhogweed.so.6.6, with sonames
libnettle.so.8 and libhogweed.so.6.