sctp: if POLLRDHUP is available, use it to check if the client disconnected.
sctp: if POLLRDHUP is available, use it to check if the client disconnected.

This allows ignoring stray 0-sized packages on Linux.

winlinvip/feng,lscube/feng,lscube/feng,lscube/feng,winlinvip/feng,winlinvip/feng