LINUX_CREAD
bts->c_cflag |= cvtto_bsd_mask(lt->c_cflag, LINUX_CREAD, CREAD);
lt->c_cflag |= cvtto_linux_mask(bts->c_cflag, CREAD, LINUX_CREAD);
bts->c_cflag |= cvtto_bsd_mask(lts->c_cflag, LINUX_CREAD, CREAD);
lts->c_cflag |= cvtto_linux_mask(bts->c_cflag, CREAD, LINUX_CREAD);