diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/wtf/Threading.h b/src/3rdparty/javascriptcore/JavaScriptCore/wtf/Threading.h
index 1f6d25e..087c3fb 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/wtf/Threading.h
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/wtf/Threading.h
@@ -81,7 +81,7 @@
 #include <pthread.h>
 #elif PLATFORM(GTK)
 #include <wtf/gtk/GOwnPtr.h>
-typedef struct _GMutex GMutex;
+typedef union _GMutex GMutex;
 typedef struct _GCond GCond;
 #endif