fix for vmware VMs

[iddq]

https://github.com/danielinux/ttybus/blob/32e9a9edda3717a1244e394dc59e02e1e469cee0/tty_attach.c#L100

-       realdev = open(devname, O_RDWR);
+       realdev = open(devname, O_RDWR|O_NOCTTY|O_NONBLOCK);

[danielinux]

tty's may be used as controlling TTY in some cases, so O_NOCTTY by default is not an option. I don't see any valid reasons to make the socket non blocking either.

Perhaps both could be configuration options if it makes sense.