Merge remote-tracking branch 'remotes/bsdimp/tags/bsd-user-preen-2022q1-pull-request...

Merge remote-tracking branch 'remotes/bsdimp/tags/bsd-user-preen-2022q1-pull-request' into staging

bsd-user: Prepare for future upstream of system calls.

This series of patches does three things.

First, it starts to give up on the idea that you can run FooBSD binaries on
BarBSD. They are too different to make that happen any time soon, though I've
kept the support for Net/OpenBSD, even though they haven't built. We'll need a
lot of work to make that happen, though, and I need to simplify to get things
upstream.

Second, it starts to move some of the ifdef trees into target.h.

Third, it starts to upstream bsd-file.h, but the remainder of the file in the
bsd-user fork had some issues that will be resolved before next quarter's
update.

# gpg: Signature made Mon 28 Feb 2022 18:11:47 GMT
# gpg:                using RSA key 2035F894B00AA3CF7CCDE1B76C1CD1287DB01100
# gpg: Good signature from "Warner Losh <wlosh@netflix.com>" [unknown]
# gpg:                 aka "Warner Losh <imp@bsdimp.com>" [unknown]
# gpg:                 aka "Warner Losh <imp@freebsd.org>" [unknown]
# gpg:                 aka "Warner Losh <imp@village.org>" [unknown]
# gpg:                 aka "Warner Losh <wlosh@bsdimp.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 2035 F894 B00A A3CF 7CCD  E1B7 6C1C D128 7DB0 1100

* remotes/bsdimp/tags/bsd-user-preen-2022q1-pull-request:
  bsd-user: Add safe system call macros
  bsd-user: Define target_arg64
  bsd-user: introduce target.h
  bsd-user/bsd-file.h: Implementation details for the filesystem calls
  bsd-user/freebsd/os-syscall.c: Add get_errno and host_to_target_errno
  bsd-user/sycall.c: Now obsolete, remove
  bsd-user: Move system call building to os-syscall.c
  bsd-user/freebsd/os-syscall.c: Move syscall processing here
  bsd-user: Remove bsd_type
  bsd-user/x86_64/target_arch_thread.h: Assume a FreeBSD target
  bsd-user/arm/target_arch_thread.h: Assume a FreeBSD target
  bsd-user/arm/target_arch_cpu.h: Only support FreeBSD sys calls
  bsd-user/i386/target_arch_cpu.h: Remove openbsd syscall
  bsd-user/x86_64/target_arch_cpu.h: Remove openbsd syscall
  bsd-user/x86_64/target_arch_cpu.h: int $80 never was a BSD system call on amd64
  bsd-user/main.c: Drop syscall flavor arg -bsd

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