instead set a flag that skips the listening socket from the poll()
event loop. The flag is cleared whenever a file descriptor is closed
allowing accept() to be retried.
Explained by deraadt@
- stream definitions (-ios) now must follow devices definitions they
are attached to (-fMn).
- the -n option is now a special "loopback" device and is thus used
like -f, eg it must precede streams
- channel numbers (-Cc options) correspond always to channel numbers
of the hardware.
- removed -u option (not needed anymore)