rtt = tt;
cfmakeraw(&rtt);
rtt.c_lflag &= ~ECHO;
+ rtt.c_lflag |= ISIG;
// block SIGTTOU during tcsetattr to prevent a hang if
// the process is a member of the background process group
// http://www.opengroup.org/onlinepubs/000095399/functions/tcsetattr.html