Index: /trunk/include/VBox/pgm.h
===================================================================
--- /trunk/include/VBox/pgm.h	(revision 29565)
+++ /trunk/include/VBox/pgm.h	(revision 29566)
@@ -41,4 +41,8 @@
  * @{
  */
+/* This must match GMMR0Init; currently we only support page fusion on all 64-bit hosts except Mac OS X */
+#if HC_ARCH_BITS == 64 && (defined(RT_OS_WINDOWS) || defined(RT_OS_SOLARIS) || defined(RT_OS_LINUX) || defined(RT_OS_FREEBSD))
+#define VBOX_WITH_PAGE_SHARING
+#endif
 
 /** Chunk size for dynamically allocated physical memory. */
Index: /trunk/src/VBox/VMM/Makefile.kmk
===================================================================
--- /trunk/src/VBox/VMM/Makefile.kmk	(revision 29565)
+++ /trunk/src/VBox/VMM/Makefile.kmk	(revision 29566)
@@ -52,7 +52,4 @@
 ifdef VBOX_WITH_RAW_MODE
  VMMR3_DEFS    += VBOX_WITH_RAW_MODE
-endif
-ifdef VBOX_WITH_PAGE_SHARING
- VMMR3_DEFS    += VBOX_WITH_PAGE_SHARING
 endif
 VMMR3_DEFS.darwin = VMM_R0_SWITCH_STACK
@@ -432,7 +429,4 @@
  VMMR0_DEFS    += VBOX_WITH_RAW_MODE
 endif
-ifdef VBOX_WITH_PAGE_SHARING
- VMMR0_DEFS    += VBOX_WITH_PAGE_SHARING
-endif
 VMMR0_DEFS.darwin = VMM_R0_SWITCH_STACK
 VMMR0_DEFS.darwin.x86 = \