Define IN6_IS_ADDR_ macros to conform to Posix Spec

(cherry picked from commit 4c2df0d02ed71ae07e85f1b35ac857a148cd2b8f)
Signed-off-by: Jonathan Yong <10walls@gmail.com>
diff --git a/mingw-w64-headers/include/ws2tcpip.h b/mingw-w64-headers/include/ws2tcpip.h
index c530d57..153f9c9 100644
--- a/mingw-w64-headers/include/ws2tcpip.h
+++ b/mingw-w64-headers/include/ws2tcpip.h
@@ -136,6 +136,20 @@
   a->sin6_scope_id = 0;
 }
 
+/* Those declarations are mandatory for Open Group Base spec */
+#define IN6_IS_ADDR_UNSPECIFIED IN6_IS_ADDR_UNSPECIFIED
+#define IN6_IS_ADDR_LOOPBACK IN6_IS_ADDR_LOOPBACK
+#define IN6_IS_ADDR_MULTICAST IN6_IS_ADDR_MULTICAST
+#define IN6_IS_ADDR_LINKLOCAL IN6_IS_ADDR_LINKLOCAL
+#define IN6_IS_ADDR_SITELOCAL IN6_IS_ADDR_SITELOCAL
+#define IN6_IS_ADDR_V4MAPPED IN6_IS_ADDR_V4MAPPED
+#define IN6_IS_ADDR_V4COMPAT IN6_IS_ADDR_V4COMPAT
+#define IN6_IS_ADDR_MC_NODELOCAL IN6_IS_ADDR_MC_NODELOCAL
+#define IN6_IS_ADDR_MC_LINKLOCAL IN6_IS_ADDR_MC_LINKLOCAL
+#define IN6_IS_ADDR_MC_SITELOCAL IN6_IS_ADDR_MC_SITELOCAL
+#define IN6_IS_ADDR_MC_ORGLOCAL IN6_IS_ADDR_MC_ORGLOCAL
+#define IN6_IS_ADDR_MC_GLOBAL IN6_IS_ADDR_MC_GLOBAL
+
 #ifdef __cplusplus
 }
 #endif