* fhandler_console.cc (fhandler_console::dup): Only set ctty when we haven't

* fhandler_console.cc (fhandler_console::dup): Only set ctty when we haven't
specifically called setsid.
* fhandler_tty.cc (fhandler_pty_slave::dup): Ditto.  Also add comment
documenting research into rxvt problem.
* fhandler_termios.cc (fhandler_termios::tcsetpgrp): Don't check specifically
for myself->ctty == -1.  Test for > 0 as that is the correct test.
(fhandler_termios::sigflush): Ditto.