Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-3.1-pull-request' into staging

- some fixes for setrlimit() and write()
- fixes ELF loader when host page size is greater than target page size
- add SO_LINGER to getsockopt()/setsockopt()
- move TargetFdTrans from syscall.c
  v2: add "#include <linux/netlink.h>" in linux-user/fd-trans.c

# gpg: Signature made Tue 25 Sep 2018 21:51:13 BST
# 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-3.1-pull-request:
  linux-user: do setrlimit selectively
  linux-user: write(fd, NULL, 0) parity with linux's treatment of same
  linux-user: elf: mmap all the target-pages of hostpage for data segment
  linux-user: add SO_LINGER to {g,s}etsockopt
  linux-user: move TargetFdTrans functions to their own file

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