diff --git a/fpdfsdk/javascript/JS_Value.cpp b/fpdfsdk/javascript/JS_Value.cpp
index 40b94fa..e52d7d1 100644
--- a/fpdfsdk/javascript/JS_Value.cpp
+++ b/fpdfsdk/javascript/JS_Value.cpp
@@ -31,12 +31,12 @@
   time_t t = 0;
   time(&t);
   localtime(&t);
-#if defined(_MSC_VER)
+#if _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_
   // In gcc 'timezone' is a global variable declared in time.h. In VC++, that
   // variable was removed in VC++ 2015, with _get_timezone replacing it.
   long timezone = 0;
   _get_timezone(&timezone);
-#endif
+#endif  // _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_
   return (double)(-(timezone * 1000));
 }