diff -up webkit-qtwebkit-23/Source/cmake/WebKitFeatures.cmake.me webkit-qtwebkit-23/Source/cmake/WebKitFeatures.cmake
--- webkit-qtwebkit-23/Source/cmake/WebKitFeatures.cmake.me	2013-02-25 15:53:12.278297141 +0100
+++ webkit-qtwebkit-23/Source/cmake/WebKitFeatures.cmake	2013-02-25 15:53:42.134167593 +0100
@@ -125,7 +125,7 @@ MACRO (WEBKIT_OPTION_BEGIN)
     WEBKIT_OPTION_DEFINE(ENABLE_WORKERS "Toggle Web Workers support" OFF)
     WEBKIT_OPTION_DEFINE(ENABLE_XHR_TIMEOUT "Toggle XHR timeout support" OFF)
     WEBKIT_OPTION_DEFINE(ENABLE_XSLT "Toggle XSLT support" ON)
-    WEBKIT_OPTION_DEFINE(USE_SYSTEM_MALLOC "Toggle system allocator instead of TCmalloc" OFF)
+    WEBKIT_OPTION_DEFINE(USE_SYSTEM_MALLOC "Toggle system allocator instead of TCmalloc" ON)
     WEBKIT_OPTION_DEFINE(WTF_USE_TILED_BACKING_STORE "Toggle Tiled Backing Store support" OFF)
     WEBKIT_OPTION_DEFINE(WTF_USE_WTFURL "Toogle the use of WTFURL for URL parsing" OFF)
 ENDMACRO ()
diff -up webkit-qtwebkit-23/Source/WTF/wtf/PageAllocationAligned.cpp.me webkit-qtwebkit-23/Source/WTF/wtf/PageAllocationAligned.cpp
--- webkit-qtwebkit-23/Source/WTF/wtf/PageAllocationAligned.cpp.me	2013-02-25 15:54:06.974227858 +0100
+++ webkit-qtwebkit-23/Source/WTF/wtf/PageAllocationAligned.cpp	2013-02-25 15:55:02.355132792 +0100
@@ -50,7 +50,9 @@ PageAllocationAligned PageAllocationAlig
     vm_map(current_task(), &address, size, alignmentMask, flags, MEMORY_OBJECT_NULL, 0, FALSE, protection, PROT_READ | PROT_WRITE | PROT_EXEC, VM_INHERIT_DEFAULT);
     return PageAllocationAligned(reinterpret_cast<void*>(address), size);
 #else
-    size_t alignmentDelta = alignment - pageSize();
+    size_t pagesize =  pageSize();
+    if (alignment < pagesize) alignment = pagesize;
+    size_t alignmentDelta = alignment - pagesize;
 
     // Resererve with suffcient additional VM to correctly align.
     size_t reservationSize = size + alignmentDelta;
--- webkit-qtwebkit-23/Source/WTF/wtf/Platform.h.system-malloc	2013-02-15 16:46:12.000000000 +0100
+++ webkit-qtwebkit-23/Source/WTF/wtf/Platform.h	2013-02-27 14:50:28.044688152 +0100
@@ -1011,7 +1011,7 @@
 #define ENABLE_REGEXP_TRACING 0
 
 /* Yet Another Regex Runtime - turned on by default for JIT enabled ports. */
-#if !defined(ENABLE_YARR_JIT) && (ENABLE(JIT) || ENABLE(LLINT_C_LOOP)) && !PLATFORM(CHROMIUM)
+#if !defined(ENABLE_YARR_JIT) && ENABLE(JIT) && !PLATFORM(CHROMIUM)
 #define ENABLE_YARR_JIT 1
 
 /* Setting this flag compares JIT results with interpreter results. */