linux-user/host/s390: Populate host_signal.h

Split host_signal_pc and host_signal_write out of user-exec.c.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
3 files changed