Fix most UDP issues on Mac OS

Fix most UDP issues on Mac OS

We still do not test getting SO_BROADCAST, as it (at least on my laptop)
returns false even if it has just been turned on.

Setting SO_REUSEADDR for datagram sockets also behaves differently
compared to Linux and Windows.

IPv6 multicast as I could not test it on my laptop.

R=ajohnsen@google.com
BUG=http://dartbug.com/1975

Committed: https://code.google.com/p/dart/source/detail?r=31223

[Anders Johnsen, 2013-12-18 11:29:48]

LGTM, with BUG= updated.

https://codereview.chromium.org/117723003/diff/1/runtime/bin/socket_macos.cc
File runtime/bin/socket_macos.cc (right):

https://codereview.chromium.org/117723003/diff/1/runtime/bin/socket_macos.cc#...
runtime/bin/socket_macos.cc:634: return JoinOrLeaveMulticast(fd, addr,
interface, interfaceIndex, true);
Indentation here and line above.

[Søren Gjesse, 2013-12-18 11:56:28]

https://codereview.chromium.org/117723003/diff/1/runtime/bin/socket_macos.cc
File runtime/bin/socket_macos.cc (right):

https://codereview.chromium.org/117723003/diff/1/runtime/bin/socket_macos.cc#...
runtime/bin/socket_macos.cc:634: return JoinOrLeaveMulticast(fd, addr,
interface, interfaceIndex, true);
On 2013/12/18 11:29:49, Anders Johnsen wrote:
> Indentation here and line above.

Done.

[Søren Gjesse, 2013-12-18 12:23:49]

Committed patchset #1 manually as r31223 (presubmit successful).