Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-4.0-pull-request...

Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-4.0-pull-request' into staging

Minor linux-user update (2019-01-10)
Fixes LTP tests pwrite03 and pwrite03_64

# gpg: Signature made Thu 10 Jan 2019 08:37:04 GMT
# gpg:                using RSA key F30C38BD3F2FBE3C
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>"
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>"
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>"
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/linux-user-for-4.0-pull-request:
  linux-user: make pwrite64/pread64(fd, NULL, 0, offset) return 0
  Add getsockopt for settable SOL_IPV6 options

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>