Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-2.12-pull-request...

Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-2.12-pull-request' into staging

# gpg: Signature made Tue 13 Mar 2018 17:33:03 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-2.12-pull-request:
  linux-user: init_guest_space: Add a comment about search strategy
  linux-user: init_guest_space: Don't try to align if we'll reject it
  linux-user: init_guest_space: Clean up control flow a bit
  linux-user: init_guest_commpage: Add a comment about size check
  linux-user: init_guest_space: Clarify page alignment logic
  linux-user: init_guest_space: Correctly handle guest_start in commpage initialization
  linux-user: init_guest_space: Clean up if we can't initialize the commpage
  linux-user: Rename validate_guest_space => init_guest_commpage
  linux-user: Use #if to only call validate_guest_space for 32-bit ARM target
  qemu-binfmt-conf.sh: add qemu-xtensa
  linux-user: drop unused target_msync function
  linux-user: fix target_mprotect/target_munmap error return values
  linux-user: fix assertion in shmdt
  linux-user: fix mmap/munmap/mprotect/mremap/shmat
  linux-user: Support f_flags in statfs when available.
  linux-user: allows to use "--systemd ALL" with qemu-binfmt-conf.sh
  linux-user: Remove the unused "not implemented" signal handling stubs
  linux-user: Drop unicore32 code

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