Problem in Lua for Windows with UDP multicast receive

[Herbert Leuwer <herbert.leuwer@...>]

I tried to add multicast membership to a datagram socket for IP multicast using udp:setoption(...), but the call allways fails.
After some browsing I found a possible cause related to this article of MSDN:

http://support.microsoft.com/kb/257460/en

Looking into the original luasocket code, I found that luasocket seems to use winsock.h while clibs\socket\core.dll seems to be 
linked against ws2_32.lib. This would be the non-tolerant header/lib combination named in the article above.

The same Lua receive script works fine in a non-Windows environment.

Sending of multicast packets works also in Windows.

I used the latest Lua for Windows version.

Thanks
-- Herbert