Use CROW_USE_LOCALTIME macro for explict optin

Author: kingster

include/crow/logging.h

@@ -72,9 +72,17 @@ namespace crow
             tm my_tm;
 
 #if defined(_MSC_VER) || defined(__MINGW32__)
+    #ifdef CROW_USE_LOCALTIME
             localtime_s(&my_tm, &t);
+    #else
+            gmtime_s(&my_tm, &t);
+    #endif
 #else
+    #ifdef CROW_USE_LOCALTIME
             localtime_r(&t, &my_tm);
+    #else
+            gmtime_r(&t, &my_tm);
+    #endif
 #endif
 
             size_t sz = strftime(date, sizeof(date), "%Y-%m-%d %H:%M:%S", &my_tm);