Import IPv6-supported Lua5.2 compatible code from Matthew Wild's repo

Signed-off-by: Vadim A. Misbakh-Soloviov <mva@mva.name>

samples/daytimeclnt.lua

@@ -0,0 +1,23 @@
+-----------------------------------------------------------------------------
+-- UDP sample: daytime protocol client
+-- LuaSocket sample files
+-- Author: Diego Nehab
+-- RCS ID: $Id: daytimeclnt.lua,v 1.11 2004/06/21 06:07:57 diego Exp $
+-----------------------------------------------------------------------------
+local socket = require"socket"
+host = host or "127.0.0.1"
+port = port or 13
+if arg then
+    host = arg[1] or host
+    port = arg[2] or port
+end
+host = socket.dns.toip(host)
+udp = socket.udp()
+print("Using host '" ..host.. "' and port " ..port.. "...")
+udp:setpeername(host, port)
+udp:settimeout(3)
+sent, err = udp:send("anything")
+if err then print(err) os.exit() end
+dgram, err = udp:receive()
+if not dgram then print(err) os.exit() end
+io.write(dgram)