--- qtwebkit/Source/WTF/wtf/Atomics.h	2016-06-09 19:14:49.225087412 +0100
+++ qtwebkit/Source/WTF/wtf/Atomics.h	2016-06-09 19:15:02.498182976 +0100
@@ -125,7 +125,7 @@
 
 inline void x86_mfence()
 {
-#if OS(WINDOWS)
+#if OS(WINDOWS) && !COMPILER(GCC)
     // I think that this does the equivalent of a dummy interlocked instruction,
     // instead of using the 'mfence' instruction, at least according to MSDN. I
     // know that it is equivalent for our purposes, but it would be good to