diff -Nur webkit-1.3.4.orig/JavaScriptCore/wtf/Platform.h webkit-1.3.4/JavaScriptCore/wtf/Platform.h
--- webkit-1.3.4.orig/JavaScriptCore/wtf/Platform.h	2010-09-22 13:09:17.000000000 -0600
+++ webkit-1.3.4/JavaScriptCore/wtf/Platform.h	2010-09-23 12:13:19.692721521 -0600
@@ -1025,7 +1025,7 @@
 #endif
 /* Setting this flag prevents the assembler from using RWX memory; this may improve
    security but currectly comes at a significant performance cost. */
-#if PLATFORM(IOS)
+#if PLATFORM(IOS) || PLATFORM(X86) || PLATFORM(X86_64)
 #define ENABLE_ASSEMBLER_WX_EXCLUSIVE 1
 #else
 #define ENABLE_ASSEMBLER_WX_EXCLUSIVE 0