--- libmalloc/libmalloc-646.0.13/src/nano_zone_common.h
+++ libmalloc/libmalloc-317.121.1/src/nano_zone_common.h
@@ -30,7 +30,7 @@
 #define NANO_QUANTA_MASK		(NANO_REGIME_QUANTA_SIZE - 1)
 #define NANO_SIZE_CLASSES		(NANO_MAX_SIZE/NANO_REGIME_QUANTA_SIZE)
 
-#if MALLOC_TARGET_IOS
+#if TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR
 
 // Nanozone follows the shared region.
 #define SHIFT_NANO_SIGNATURE	29
@@ -38,18 +38,14 @@
 #define NANOZONE_BASE_REGION_ADDRESS (SHARED_REGION_BASE + SHARED_REGION_SIZE)
 #define NANOZONE_SIGNATURE (NANOZONE_BASE_REGION_ADDRESS >> SHIFT_NANO_SIGNATURE)
 
-#else // MALLOC_TARGET_IOS
+#else // TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR
 
 #define SHIFT_NANO_SIGNATURE	44
 #define NANOZONE_SIGNATURE_BITS	20
 #define NANOZONE_SIGNATURE		0x6ULL
 #define NANOZONE_BASE_REGION_ADDRESS (NANOZONE_SIGNATURE << SHIFT_NANO_SIGNATURE)
 
-#endif // MALLOC_TARGET_IOS
-
-
-MALLOC_STATIC_ASSERT((SHIFT_NANO_SIGNATURE + NANOZONE_SIGNATURE_BITS) == 64, 
-		"Nano addresses must be 64 bits wide");
+#endif // TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR
 
 static MALLOC_INLINE size_t
 _nano_common_good_size(size_t size)