From 398e0421a116f223ee61f487e22ad0743d422777 Mon Sep 17 00:00:00 2001
From: Thulinma <jaron@vietors.com>
Date: Wed, 23 Jul 2014 13:14:07 +0200
Subject: [PATCH] Windows dual-stack support.

---
 lib/socket.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/socket.cpp b/lib/socket.cpp
index 5e40ffc9..b2415bf2 100644
--- a/lib/socket.cpp
+++ b/lib/socket.cpp
@@ -746,6 +746,10 @@ bool Socket::Server::IPv6bind(int port, std::string hostname, bool nonblock) {
   }
   int on = 1;
   setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+#ifdef __CYGWIN__
+  on = 0;
+  setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on));
+#endif
   if (nonblock) {
     int flags = fcntl(sock, F_GETFL, 0);
     flags |= O_NONBLOCK;