check_c_source_compiles (
                         "${PLIBSYS_SOCKET_INCLUDES}
                          int main () {
                                struct sockaddr_in6 sock_addr;
                                sock_addr.sin6_flowinfo = 0;

                                return 0;
                          }"
                          PLIBSYS_SOCKADDR_IN6_HAS_FLOWINFO
                        )