Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-2.13-pull-request...

Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-2.13-pull-request' into staging

# gpg: Signature made Thu 03 May 2018 22:38:35 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-2.13-pull-request:
  linux-user: remove useless padding in flock64 structure
  linux-user: introduce target_sigsp() and target_save_altstack()
  linux-user: ARM-FDPIC: Add support for signals for FDPIC targets
  linux-user: ARM-FDPIC: Add support of FDPIC for ARM.
  linux-user: ARM-FDPIC: Identify ARM FDPIC binaries
  Remove CONFIG_USE_FDPIC.

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