core: fix Bullet compilation with the Native Client toolchain.

src/bullet/BulletCollision/BroadphaseCollision/btDbvt.h

@@ -92,7 +92,7 @@ subject to the following restrictions:
 #endif
 
 #if DBVT_USE_MEMMOVE
-#if !defined( __CELLOS_LV2__) && !defined(__MWERKS__)
+#if !defined( __CELLOS_LV2__) && !defined(__MWERKS__) && !defined(__native_client__)
 #include <memory.h>
 #endif
 #include <string.h>

src/bullet/LinearMath/btSerializer.h

@@ -20,7 +20,7 @@ subject to the following restrictions:
 #include "btStackAlloc.h"
 #include "btHashMap.h"
 
-#if !defined( __CELLOS_LV2__) && !defined(__MWERKS__)
+#if !defined( __CELLOS_LV2__) && !defined(__MWERKS__) && !defined(__native_client__)
 #include <memory.h>
 #endif
 #include <string.h>