cmake PLIBSYS_HAS_SOCKADDR_STORAGE examples

saprykin/plibsys src/CMakeLists.txt :654

check_c_source_compiles (
                         "${PLIBSYS_SOCKET_INCLUDES}
                          int main () {
                                struct sockaddr_storage sock_addr;
                                sock_addr.ss_family = AF_INET;

                                return 0;
                          }"
                          PLIBSYS_HAS_SOCKADDR_STORAGE
                        )