message: [Utils] Use gmtime_s with _WIN32
  This allows the project to build in WSL/Ubuntu 20.04 x64
  and potentially other Windows versions.
diff: @@ -79,7 +79,7 @@ void MilliSleep(int64_t n)
  std::string FormatISO8601DateTime(int64_t nTime) {
  struct tm ts;
  time_t time_val = nTime;
  -#ifdef _MSC_VER
  +#if defined(_MSC_VER) || defined(_WIN32)
  gmtime_s(&ts, &time_val);
  #else
  gmtime_r(&time_val, &ts);
  @@ -90,7 +90,7 @@ std::string FormatISO8601DateTime(int64_t nTime) {
  std::string FormatISO8601Date(int64_t nTime) {
  struct tm ts;
  time_t time_val = nTime;
  -#ifdef _MSC_VER
  +#if defined(_MSC_VER) || defined(_WIN32)
  gmtime_s(&ts, &time_val);
  #else
  gmtime_r(&time_val, &ts);
  @@ -101,7 +101,7 @@ std::string FormatISO8601Date(int64_t nTime) {
  std::string FormatISO8601Time(int64_t nTime) {
  struct tm ts;
  time_t time_val = nTime;
  -#ifdef _MSC_VER
  +#if defined(_MSC_VER) || defined(_WIN32)
  gmtime_s(&ts, &time_val);
  #else
  gmtime_r(&time_val, &ts);
  