Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-5.1-pull-request' into staging

linux-user pull request 20200605-v2

Implement F_OFD_ fcntl() command, /proc/cpuinfo for hppa
Fix socket(), prnctl() error codes, underflow in target_mremap,
    epoll_create() strace, oldumount for alpha
User-mode build dependencies improvement

# gpg: Signature made Sat 06 Jun 2020 14:15:36 BST
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "laurent@vivier.eu"
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" [full]
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/linux-user-for-5.1-pull-request:
  stubs: Restrict ui/win32-kbd-hook to system-mode
  hw/core: Restrict CpuClass::get_crash_info() to system-mode
  target/s390x: Restrict CpuClass::get_crash_info() to system-mode
  target/i386: Restrict CpuClass::get_crash_info() to system-mode
  arch_init: Remove unused 'qapi-commands-misc.h' include
  exec: Assert CPU migration is not used on user-only build
  target/riscv/cpu: Restrict CPU migration to system-mode
  stubs/Makefile: Reduce the user-mode object list
  util/Makefile: Reduce the user-mode object list
  tests/Makefile: Restrict some softmmu-only tests
  tests/Makefile: Only display TCG-related tests when TCG is available
  configure: Avoid building TCG when not needed
  Makefile: Only build virtiofsd if system-mode is enabled
  linux-user: implement OFD locks
  linux-user/mmap.c: fix integer underflow in target_mremap
  linux-user/strace.list: fix epoll_create{,1} -strace output
  linux-user: Add support for /proc/cpuinfo on hppa platform
  linux-user: return target error codes for socket() and prctl()
  linux-user, alpha: fix oldumount syscall

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