diff --git a/libs/tk/ztk/config.h b/libs/tk/ztk/config.h
index d94a870710..86e48cac39 100644
--- a/libs/tk/ztk/config.h
+++ b/libs/tk/ztk/config.h
@@ -11,4 +11,8 @@
 #define VERSION "2.14.0"
 
 /* defines how to decorate public symbols while building */
-/* #undef _ATK_EXTERN */
+#ifdef _MSC_VER
+#define _ATK_EXTERN __declspec (dllexport) extern
+#else
+#define _ATK_EXTERN __attribute__((visibility("default"))) __declspec (dllexport) extern
+#endif