--- libmalloc/libmalloc-374.100.5/src/nanov2_zone.h
+++ libmalloc/libmalloc-792.80.2/src/nanov2_zone.h
@@ -29,21 +29,22 @@
 #pragma mark -
 #pragma mark Address Structure
 
-#if TARGET_OS_OSX || TARGET_OS_SIMULATOR || TARGET_OS_DRIVERKIT
+#if TARGET_OS_OSX || TARGET_OS_SIMULATOR || MALLOC_TARGET_DK_OSX
 
 #define NANOV2_REGION_BITS		15
 #define NANOV2_ARENA_BITS		3
 #define NANOV2_BLOCK_BITS		12
 #define NANOV2_OFFSET_BITS		14
 
-#else // TARGET_OS_OSX || TARGET_OS_SIMULATOR || TARGET_OS_DRIVERKIT
+#else // TARGET_OS_OSX || TARGET_OS_SIMULATOR || MALLOC_TARGET_DK_OSX
 
 #define NANOV2_REGION_BITS		0
 #define NANOV2_ARENA_BITS		3
 #define NANOV2_BLOCK_BITS		12
 #define NANOV2_OFFSET_BITS		14
 
-#endif // TARGET_OS_OSX || TARGET_OS_SIMULATOR || TARGET_OS_DRIVERKIT
+#endif // TARGET_OS_OSX || TARGET_OS_SIMULATOR || MALLOC_TARGET_DK_OSX
+
 
 #if NANOV2_REGION_BITS > 0
 #define NANOV2_MULTIPLE_REGIONS	1
@@ -69,7 +70,7 @@
 // Maximum number of slots per block
 #define NANOV2_MAX_SLOTS_PER_BLOCK	(NANOV2_BLOCK_SIZE/NANO_REGIME_QUANTA_SIZE)
 
-// Highest region number.
+// Highest region number supported by this signature
 #if NANOV2_MULTIPLE_REGIONS
 #define NANOV2_MAX_REGION_NUMBER	((1 << NANOV2_REGION_BITS) - 1)
 #else 	// NANOV2_MULTIPLE_REGIONS
@@ -181,8 +182,10 @@
 // Structure overlaid on slots that are on the block freelist.
 typedef struct {
     uint64_t double_free_guard;
-    uint16_t next_slot;
+    uint64_t next_slot; // Legal values are <= NEXT_SLOT_VALID_MASK
 } nanov2_free_slot_t;
+
+#define NEXT_SLOT_VALID_MASK 0x7ff
 
 MALLOC_STATIC_ASSERT(
 		sizeof(nanov2_free_slot_t) <= NANO_REGIME_QUANTA_SIZE,
@@ -258,9 +261,6 @@
 
 	// Locks for the current allocation blocks.
 	_malloc_lock_s		current_block_lock[NANO_SIZE_CLASSES][MAX_CURRENT_BLOCKS];
-
-	// Lock for delegate_allocations.
-	_malloc_lock_s		delegate_allocations_lock;
 
 	// Mask of size classes for which allocation should be delegated when a new
 	// block is needed and the class has become full.