librdmacm: Define streaming over RDMA interface (rsockets)

librdmacm: Define streaming over RDMA interface (rsockets)

Introduces a new set of APIs that support a byte streaming interface
over RDMA devices.  The new interface matches sockets, except that all
function calls are prefixed with an 'r'.

The following functions are defined:

rsocket
rbind, rlisten, raccept, rconnect
rshutdown, rclose
rrecv, rrecvfrom, rrecvmsg, rread, rreadv
rsend, rsendto, rsendmsg, rwrite, rwritev
rpoll, rselect
rgetpeername, rgetsockname
rsetsockopt, rgetsockopt, rfcntl

Functions take the same parameters as that use for sockets.  The
follow capabilities and flags are supported at this time:

PF_INET, PF_INET6, SOCK_STREAM, IPPROTO_TCP
MSG_DONTWAIT, MSG_PEEK
SO_REUSEADDR, TCP_NODELAY, SO_ERROR, SO_SNDBUF, SO_RCVBUF
O_NONBLOCK

The rpoll call supports polling both rsockets and normal fd's.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>