--- libmalloc/libmalloc-657.60.21/src/malloc.c
+++ libmalloc/libmalloc-646.40.3/src/malloc.c
@@ -1363,11 +1363,11 @@
 		max_medium_magazines = max_magazines;
 	}
 
-	// Don't enable for pre-AMP iOS hardware, which we identify as "iOS, plain
-	// arm64"
-#if CONFIG_MAGAZINE_PER_CLUSTER && \
-		(MALLOC_TARGET_IOS_ONLY || MALLOC_TARGET_DK_IOS) && \
-		defined(__arm64__) && !defined(__arm64e__)
+	// The "single-cluster" concept doesn't apply to macOS: there is no
+	// non-Intel real hardware without multiple AMP clusters, so this will only
+	// happen under virtualization, and for that case we'd prefer the
+	// straight-to-pcpu behaviour rather than falling back to the old allocator.
+#if CONFIG_MAGAZINE_PER_CLUSTER && !(TARGET_OS_OSX || MALLOC_TARGET_DK_OSX)
 	if (ncpuclusters == 1) {
 #if CONFIG_FEATUREFLAGS_SIMPLE
 		// Not with the other feature flag checks because ncpuclusters needs to
@@ -1381,7 +1381,7 @@
 			malloc_xzone_enabled = false;
 		}
 	}
-#endif
+#endif // CONFIG_MAGAZINE_PER_CLUSTER && !(TARGET_OS_OSX || MALLOC_TARGET_DK_OSX)
 
 	_malloc_detect_interposition();
 
@@ -2912,12 +2912,7 @@
 	void *ptr = realloc(in_ptr, new_size);
 
 	if (!ptr && in_ptr && new_size != 0) {
-		// Save and restore `errno`, because `realloc` will set it to ENOMEM
-		// on allocation failure, but it could be overwritten if `free` calls
-		// into a library function that also modifies `errno`
-		errno_t error = errno;
 		free(in_ptr);
-		errno = error;
 	}
 
 	return ptr;