* fhandler_socket (fhandler_socket::readv): Call recv_internal directly,
rather than recvmsg.
(fhandler_socket::writev): Call send_internal directly, rather than
sendmsg.
* net.cc (cygwin_recv): Call fhandler_socket::recvfrom directly, rather
than cygwin_recvfrom.
(cygwin_send): Call fhandler_socket::sendto directly, rather than
cygwin_sendto.