Function getCurrentTimestamp

extlibs/catch/include/catch/catch.hpp:15965–15989

    namespace {
        std::string getCurrentTimestamp() {
            // Beware, this is not reentrant because of backward compatibility issues
            // Also, UTC only, again because of backward compatibility (%z is C++11)
            time_t rawtime;
            std::time(&rawtime);
            auto const timeStampSize = sizeof("2017-01-16T17:06:45Z");

#ifdef _MSC_VER
            std::tm timeInfo = {};
            gmtime_s(&timeInfo, &rawtime);
#else
            std::tm* timeInfo;
            timeInfo = std::gmtime(&rawtime);
#endif

            char timeStamp[timeStampSize];
            const char * const fmt = "%Y-%m-%dT%H:%M:%SZ";

#ifdef _MSC_VER
            std::strftime(timeStamp, timeStampSize, fmt, &timeInfo);
#else
            std::strftime(timeStamp, timeStampSize, fmt, timeInfo);
#endif
            return std::string(timeStamp);
        }

        std::string fileNameTag(const std::vector<std::string> &tags) {
            auto it = std::find_if(begin(tags),