Do not disable RFC3678 multicast API on Windows

The API is supported since Windows Vista and requires targeting Vista
when compiling PHP. Pierre had asked to disable this by default, even
when targeting Vista/Windows Server 2008.

Since XP will not be supported anymore on php-next, any rationale
for this option will not apply anymore.

Author: cataphract

Diff for: ext/sockets/multicast.h

@@ -18,9 +18,7 @@
 
 /* $Id$ */
 
-#if defined(MCAST_JOIN_GROUP) && \
-	(!defined(PHP_WIN32) || (_WIN32_WINNT >= 0x600 && SOCKETS_ENABLE_VISTA_API)) && \
-	!defined(__APPLE__)
+#if defined(MCAST_JOIN_GROUP) && !defined(__APPLE__)
 #define RFC3678_API 1
 /* has block/unblock and source membership, in this case for both IPv4 and IPv6 */
 #define HAS_MCAST_EXT 1