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.
The multicast support in PHP 5.4 makes use of MCAST_JOIN_GROUP if it is present.
The problem is that OSX 10.7 added the constant, but did not correctly implement
the feature. This causes the setsockopt call to fail.
The solution to the problem is to not use MCAST_JOIN_GROUP on OSX.
For reference, this was also done in VLC:
* http://trac.videolan.org/vlc/ticket/6104#comment:19
