If there is a TTY, we have to determine who it belongs to before we can proceed. If this is a slave editor or graphical debugger (denoted by the first command-line switch being '-emacs'), we shift this off and set $rl to 0 (XXX ostensibly to do straight reads).

We then determine what the console should be on various systems:

    Cygwin - We use stdin instead of a separate device.
    Windows or MSDOS - use con.
    AmigaOS - use CONSOLE:.
    VMS - use sys$command.
    Unix - use /dev/tty.