Merge tag 'pull-lu-20211123' of https://gitlab.com/rth7680/qemu into staging

Create common rewind_if_in_safe_syscall function.
Resolves pointer type issues with uc_mcontext.pc
on aarch64 between glibc and musl.

# gpg: Signature made Tue 23 Nov 2021 09:47:07 AM CET
# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [ultimate]

* tag 'pull-lu-20211123' of https://gitlab.com/rth7680/qemu:
  linux-user/signal.c: Create a common rewind_if_in_safe_syscall
  linux-user: Add host_signal_set_pc to set pc in mcontext

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