convbin: workaround gmtime_r for windows WIN32

MSC has gmtime_s, but not BCC which has gmtime_r.

Author: ourairquality

app/consapp/convbin/convbin.c

@@ -403,7 +403,11 @@ static int get_filetime(const char *file, gtime_t *time)
     struct stat st;
     if (!stat(path, &st)) {
         struct tm tm;
+#ifdef _MSC_VER
+        if (gmtime_s(&tm, &st.st_mtime)) {
+#else
         if (gmtime_r(&st.st_mtime, &tm)) {
+#endif
           double ep[6];
           ep[0] = tm.tm_year + 1900;
           ep[1] = tm.tm_mon + 1;