--- libmalloc/libmalloc-166.251.2/src/locking.h
+++ libmalloc/libmalloc-646.0.13/src/locking.h
@@ -24,47 +24,129 @@
 #ifndef __LOCKING_H
 #define __LOCKING_H
 
-#if OS_UNFAIR_LOCK_INLINE
-#define os_unfair_lock_lock_with_options(lock, options) \
+typedef struct lock_exclaves_s {
+	// Must match liblibc/include/libc/std/pthread.h
+	uint32_t _Alignas(16) opaque[4];
+} lock_exclave;
+
+// Exclaves always uses pthread.h to avoid alignment difference with os/lock.h
+#if !MALLOC_TARGET_EXCLAVES && !MALLOC_TARGET_EXCLAVES_INTROSPECTOR && __has_include(<os/lock.h>)
+# define MALLOC_HAS_OS_LOCK 1
+# include <os/lock.h>
+# if __has_include(<os/lock_private.h>)
+#  include <os/lock_private.h>
+# endif // __has_include(<os/lock_private.h>)
+# if defined(OS_UNFAIR_LOCK_INLINE) && OS_UNFAIR_LOCK_INLINE
+#  define os_unfair_lock_lock_with_options(lock, options) \
 		os_unfair_lock_lock_with_options_inline(lock, options)
-#define os_unfair_lock_trylock(lock) \
+#  define os_unfair_lock_trylock(lock) \
 		os_unfair_lock_trylock_inline(lock)
-#define os_unfair_lock_unlock(lock) \
+#  define os_unfair_lock_unlock(lock) \
 		os_unfair_lock_unlock_inline(lock)
-#endif // OS_UNFAIR_LOCK_INLINE
+# endif // defined(OS_UNFAIR_LOCK_INLINE) && OS_UNFAIR_LOCK_INLINE
 
 typedef os_unfair_lock _malloc_lock_s;
-#define _MALLOC_LOCK_INIT OS_UNFAIR_LOCK_INIT
+# define _MALLOC_LOCK_INIT OS_UNFAIR_LOCK_INIT
+#elif __has_include(<pthread.h>)
+# define MALLOC_HAS_OS_LOCK 0
+# include <pthread.h>
+
+# if MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+typedef lock_exclave _malloc_lock_s;
+
+#  define _MALLOC_LOCK_INIT (lock_exclave){0}
+# else
+_Static_assert(sizeof(lock_exclave) == sizeof(pthread_mutex_t),
+	"lock_exclave size must match pthread_mutex_t on EC");
+_Static_assert(_Alignof(lock_exclave) == _Alignof(pthread_mutex_t),
+	"lock_exclave alignment must match pthread_mutex_t on EC");
+
+typedef pthread_mutex_t _malloc_lock_s;
+#  define _MALLOC_LOCK_INIT (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER
+# endif // MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+#else
+# error "No platform locking support!"
+#endif // __has_include(<os/lock.h>)
 
 __attribute__((always_inline))
 static inline void
 _malloc_lock_init(_malloc_lock_s *lock) {
-    *lock = OS_UNFAIR_LOCK_INIT;
+#if !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+	*lock = _MALLOC_LOCK_INIT;
+#else
+	malloc_zone_error(MALLOC_ABORT_ON_ERROR, false,
+			"exclaves lock not supported");
+#endif // !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
 }
 
 MALLOC_ALWAYS_INLINE
 static inline void
 _malloc_lock_lock(_malloc_lock_s *lock) {
-	return os_unfair_lock_lock_with_options(lock,
-			OS_UNFAIR_LOCK_DATA_SYNCHRONIZATION);
+#if !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+# if MALLOC_HAS_OS_LOCK
+#  if __has_include(<os/lock_private.h>)
+	return os_unfair_lock_lock_with_options(lock, OS_UNFAIR_LOCK_ADAPTIVE_SPIN |
+											OS_UNFAIR_LOCK_DATA_SYNCHRONIZATION);
+#  else
+	return os_unfair_lock_lock(lock);
+#  endif // __has_include(<os/lock_private.h>)
+# else
+	if (pthread_mutex_lock(lock)) {
+		malloc_zone_error(MALLOC_ABORT_ON_ERROR, false,
+				"Failed to acquire lock %p!\n", lock);
+	}
+# endif // MALLOC_HAS_OS_LOCK
+#else
+	malloc_zone_error(MALLOC_ABORT_ON_ERROR, false,
+			"exclaves lock not supported");
+#endif // !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
 }
 
 MALLOC_ALWAYS_INLINE
 static inline bool
 _malloc_lock_trylock(_malloc_lock_s *lock) {
-    return os_unfair_lock_trylock(lock);
+#if !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+# if MALLOC_HAS_OS_LOCK
+	return os_unfair_lock_trylock(lock);
+# else
+    return !pthread_mutex_trylock(lock);
+# endif // MALLOC_HAS_OS_LOCK
+#else
+	malloc_zone_error(MALLOC_REPORT_CRASH, false,
+			"exclaves lock not supported");
+	return false;
+#endif // !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
 }
 
 MALLOC_ALWAYS_INLINE
 static inline void
 _malloc_lock_unlock(_malloc_lock_s *lock) {
-    return os_unfair_lock_unlock(lock);
+#if !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+# if MALLOC_HAS_OS_LOCK
+	os_unfair_lock_unlock(lock);
+# else
+	if (pthread_mutex_unlock(lock)) {
+		malloc_zone_error(MALLOC_ABORT_ON_ERROR, false,
+				"Failed to release lock %p!\n", lock);
+	}
+# endif // MALLOC_HAS_OS_LOCK
+#else
+	malloc_zone_error(MALLOC_ABORT_ON_ERROR, false,
+			"exclaves lock not supported");
+#endif // !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
 }
 
 MALLOC_ALWAYS_INLINE
 static inline void
 _malloc_lock_assert_owner(_malloc_lock_s *lock) {
+#if !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+# if MALLOC_HAS_OS_LOCK
 	os_unfair_lock_assert_owner(lock);
+# endif // MALLOC_HAS_OS_LOCK
+#else
+	malloc_zone_error(MALLOC_ABORT_ON_ERROR, false,
+			"exclaves lock not supported");
+#endif // !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
 }
 
 #endif // __LOCKING_H