cmake HAVE_TIME_T_UNSIGNED examples

percona/percona-server extra/curl/curl-8.14.1/CMakeLists.txt :1958 

check_c_source_runs("
    #include <time.h>
    int main(void) {
      time_t t = -1;
      return t < 0;
    }" HAVE_TIME_T_UNSIGNED)

percona/percona-xtradb-cluster extra/curl/curl-8.12.1/CMakeLists.txt :1867 

check_c_source_runs("
    #include <time.h>
    int main(void) {
      time_t t = -1;
      return t < 0;
    }" HAVE_TIME_T_UNSIGNED)

mysql/mysql-server extra/curl/curl-8.14.1/CMakeLists.txt :1958 

check_c_source_runs("
    #include <time.h>
    int main(void) {
      time_t t = -1;
      return t < 0;
    }" HAVE_TIME_T_UNSIGNED)