Added ares_getnameinfo which mimics the getnameinfo API

ares_ipv6.h

@@ -28,6 +28,17 @@ struct in6_addr
 };
 #endif
 
+#ifndef HAVE_STRUCT_SOCKADDR_IN6
+struct sockaddr_in6
+{
+  unsigned short  sin6_family;
+  unsigned short  sin6_port;
+  unsigned long   sin6_flowinfo;
+  struct in6_addr sin6_addr;
+  unsigned int    sin6_scope_id;
+};
+#endif
+
 #ifndef NS_IN6ADDRSZ
 #if SIZEOF_STRUCT_IN6_ADDR == 0
 /* We cannot have it set to zero, so we pick a fixed value here */
@@ -45,4 +56,12 @@ struct in6_addr
 #define NS_INT16SZ 2
 #endif
 
+#ifndef IF_NAMESIZE
+#ifdef IFNAMSIZ
+#define IF_NAMESIZE IFNAMSIZ
+#else
+#define IF_NAMESIZE 256
+#endif
+#endif
+
 #endif /* ARES_IPV6_H */