a221247430
Split out the non-ARM specific portions of SYS_ISTTY to a reusable function. This handles all GuestFD. Add a common_semi_istty_cb helper to translate the Posix error return, 0+ENOTTY, to the Arm semihosting not-a-file success result. Reviewed-by: Luc Michel <lmichel@kalray.eu> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>