ws2_32: Implement IP_UNICAST_IF socket option.

dlls/ws2_32/socket.c

@@ -383,6 +383,9 @@ static const int ws_ip_map[][2] =
 #ifdef IP_PKTINFO
     MAP_OPTION( IP_PKTINFO ),
 #endif
+#ifdef IP_UNICAST_IF
+    MAP_OPTION( IP_UNICAST_IF ),
+#endif
 };
 
 static const int ws_ipv6_map[][2] =
@@ -2846,6 +2849,9 @@ INT WINAPI WS_getsockopt(SOCKET s, INT level,
 #endif
         case WS_IP_TOS:
         case WS_IP_TTL:
+#ifdef IP_UNICAST_IF
+        case WS_IP_UNICAST_IF:
+#endif
             if ( (fd = get_sock_fd( s, 0, NULL )) == -1)
                 return SOCKET_ERROR;
             convert_sockopt(&level, &optname);
@@ -4268,6 +4274,9 @@ int WINAPI WS_setsockopt(SOCKET s, int level, int optname,
 #endif
         case WS_IP_TOS:
         case WS_IP_TTL:
+#ifdef IP_UNICAST_IF
+        case WS_IP_UNICAST_IF:
+#endif
             convert_sockopt(&level, &optname);
             break;
         case WS_IP_DONTFRAGMENT: