Merge tag 'pull-user-20211220' of https://gitlab.com/rth7680/qemu into staging

Move errno processing from safe_syscall() to safe_syscall_base().
Move safe_syscall() from linux-user to common-user.
Add FreeBSD support to safe_syscall_base().
Tidy top-level meson.build wrt {bsd,linux}-user.

# gpg: Signature made Mon 20 Dec 2021 11:46:11 AM PST
# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [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: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* tag 'pull-user-20211220' of https://gitlab.com/rth7680/qemu

:
  meson: Move bsd_user_ss to bsd-user/
  meson: Move linux_user_ss to linux-user/
  linux-user: Move thunk.c from top-level
  common-user: Adjust system call return on FreeBSD
  common-user: Move safe-syscall.* from linux-user
  bsd-user: Create special-errno.h
  linux-user: Create special-errno.h
  linux-user: Rename TARGET_QEMU_ESIGRETURN to QEMU_ESIGRETURN
  bsd-user: Rename TARGET_ERESTARTSYS to QEMU_ERESTARTSYS
  linux-user: Rename TARGET_ERESTARTSYS to QEMU_ERESTARTSYS
  linux-user: Remove HAVE_SAFE_SYSCALL and hostdep.h
  linux-user/host/sparc64: Add safe-syscall.inc.S
  linux-user/host/mips: Add safe-syscall.inc.S
  linux-user: Move syscall error detection into safe_syscall_base
  linux-user: Untabify all safe-syscall.inc.S

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>