websocket backend

[djczaski]

What are the best options for websocket backends?  I'm working with an
embedded platform so I'm somewhat restricted to something lightweight
in C/C++.  The things I found so far are:

libwebsockets: http://git.warmcat.com/cgi-bin/cgit/libwebsockets/
poco: http://www.appinf.com/docs/poco/Poco.Net.WebSocket.html

Another option would be to handle it right in Openresty/ngx_lua.  I
see there was some discussion about this a little while back:

https://github.com/chaoslawful/lua-nginx-module/issues/165

What are the best options?