cmake PLIBSYS_HAS_GETADDRINFO examples

saprykin/plibsys src/CMakeLists.txt :472

check_c_source_compiles (
                                 "#include <sys/socket.h>
                                  #include <netdb.h>
                                 int main () {
                                        getaddrinfo (0, 0, 0, 0);
                                        freeaddrinfo (0);

                                        return 0;
                                 }"
                                 PLIBSYS_HAS_GETADDRINFO
                                )