diff --git a/libc/bionic/pthread.c b/libc/bionic/pthread.c
index e1ace7d..88a972d 100644
--- a/libc/bionic/pthread.c
+++ b/libc/bionic/pthread.c
@@ -101,8 +101,8 @@
     .sched_priority = 0
 };
 
-__LIBC_HIDDEN__ pthread_internal_t* gThreadList = NULL;
-__LIBC_HIDDEN__ pthread_mutex_t gThreadListLock = PTHREAD_MUTEX_INITIALIZER;
+static pthread_internal_t* gThreadList = NULL;
+static pthread_mutex_t gThreadListLock = PTHREAD_MUTEX_INITIALIZER;
 static pthread_mutex_t gDebuggerNotificationLock = PTHREAD_MUTEX_INITIALIZER;
 
 static void _pthread_internal_remove_locked(pthread_internal_t* thread) {
@@ -550,6 +550,9 @@
         c->__cleanup_routine(c->__cleanup_arg);
 }
 
+/* used by pthread_exit() to clean all TLS keys of the current thread */
+static void pthread_key_clean_all(void);
+
 void pthread_exit(void * retval)
 {
     pthread_internal_t*  thread     = __get_thread();
@@ -1777,6 +1780,303 @@
 }
 
 
+
+/* A technical note regarding our thread-local-storage (TLS) implementation:
+ *
+ * There can be up to TLSMAP_SIZE independent TLS keys in a given process,
+ * though the first TLSMAP_START keys are reserved for Bionic to hold
+ * special thread-specific variables like errno or a pointer to
+ * the current thread's descriptor.
+ *
+ * while stored in the TLS area, these entries cannot be accessed through
+ * pthread_getspecific() / pthread_setspecific() and pthread_key_delete()
+ *
+ * also, some entries in the key table are pre-allocated (see tlsmap_lock)
+ * to greatly simplify and speedup some OpenGL-related operations. though the
+ * initialy value will be NULL on all threads.
+ *
+ * you can use pthread_getspecific()/setspecific() on these, and in theory
+ * you could also call pthread_key_delete() as well, though this would
+ * probably break some apps.
+ *
+ * The 'tlsmap_t' type defined below implements a shared global map of
+ * currently created/allocated TLS keys and the destructors associated
+ * with them. You should use tlsmap_lock/unlock to access it to avoid
+ * any race condition.
+ *
+ * the global TLS map simply contains a bitmap of allocated keys, and
+ * an array of destructors.
+ *
+ * each thread has a TLS area that is a simple array of TLSMAP_SIZE void*
+ * pointers. the TLS area of the main thread is stack-allocated in
+ * __libc_init_common, while the TLS area of other threads is placed at
+ * the top of their stack in pthread_create.
+ *
+ * when pthread_key_create() is called, it finds the first free key in the
+ * bitmap, then set it to 1, saving the destructor altogether
+ *
+ * when pthread_key_delete() is called. it will erase the key's bitmap bit
+ * and its destructor, and will also clear the key data in the TLS area of
+ * all created threads. As mandated by Posix, it is the responsability of
+ * the caller of pthread_key_delete() to properly reclaim the objects that
+ * were pointed to by these data fields (either before or after the call).
+ *
+ */
+
+/* TLS Map implementation
+ */
+
+#define TLSMAP_START      (TLS_SLOT_MAX_WELL_KNOWN+1)
+#define TLSMAP_SIZE       BIONIC_TLS_SLOTS
+#define TLSMAP_BITS       32
+#define TLSMAP_WORDS      ((TLSMAP_SIZE+TLSMAP_BITS-1)/TLSMAP_BITS)
+#define TLSMAP_WORD(m,k)  (m)->map[(k)/TLSMAP_BITS]
+#define TLSMAP_MASK(k)    (1U << ((k)&(TLSMAP_BITS-1)))
+
+/* this macro is used to quickly check that a key belongs to a reasonable range */
+#define TLSMAP_VALIDATE_KEY(key)  \
+    ((key) >= TLSMAP_START && (key) < TLSMAP_SIZE)
+
+/* the type of tls key destructor functions */
+typedef void (*tls_dtor_t)(void*);
+
+typedef struct {
+    int         init;                  /* see comment in tlsmap_lock() */
+    uint32_t    map[TLSMAP_WORDS];     /* bitmap of allocated keys */
+    tls_dtor_t  dtors[TLSMAP_SIZE];    /* key destructors */
+} tlsmap_t;
+
+static pthread_mutex_t  _tlsmap_lock = PTHREAD_MUTEX_INITIALIZER;
+static tlsmap_t         _tlsmap;
+
+/* lock the global TLS map lock and return a handle to it */
+static __inline__ tlsmap_t* tlsmap_lock(void)
+{
+    tlsmap_t*   m = &_tlsmap;
+
+    pthread_mutex_lock(&_tlsmap_lock);
+    /* we need to initialize the first entry of the 'map' array
+     * with the value TLS_DEFAULT_ALLOC_MAP. doing it statically
+     * when declaring _tlsmap is a bit awkward and is going to
+     * produce warnings, so do it the first time we use the map
+     * instead
+     */
+    if (__unlikely(!m->init)) {
+        TLSMAP_WORD(m,0) = TLS_DEFAULT_ALLOC_MAP;
+        m->init          = 1;
+    }
+    return m;
+}
+
+/* unlock the global TLS map */
+static __inline__ void tlsmap_unlock(tlsmap_t*  m)
+{
+    pthread_mutex_unlock(&_tlsmap_lock);
+    (void)m;  /* a good compiler is a happy compiler */
+}
+
+/* test to see wether a key is allocated */
+static __inline__ int tlsmap_test(tlsmap_t*  m, int  key)
+{
+    return (TLSMAP_WORD(m,key) & TLSMAP_MASK(key)) != 0;
+}
+
+/* set the destructor and bit flag on a newly allocated key */
+static __inline__ void tlsmap_set(tlsmap_t*  m, int  key, tls_dtor_t  dtor)
+{
+    TLSMAP_WORD(m,key) |= TLSMAP_MASK(key);
+    m->dtors[key]       = dtor;
+}
+
+/* clear the destructor and bit flag on an existing key */
+static __inline__ void  tlsmap_clear(tlsmap_t*  m, int  key)
+{
+    TLSMAP_WORD(m,key) &= ~TLSMAP_MASK(key);
+    m->dtors[key]       = NULL;
+}
+
+/* allocate a new TLS key, return -1 if no room left */
+static int tlsmap_alloc(tlsmap_t*  m, tls_dtor_t  dtor)
+{
+    int  key;
+
+    for ( key = TLSMAP_START; key < TLSMAP_SIZE; key++ ) {
+        if ( !tlsmap_test(m, key) ) {
+            tlsmap_set(m, key, dtor);
+            return key;
+        }
+    }
+    return -1;
+}
+
+
+int pthread_key_create(pthread_key_t *key, void (*destructor_function)(void *))
+{
+    uint32_t   err = ENOMEM;
+    tlsmap_t*  map = tlsmap_lock();
+    int        k   = tlsmap_alloc(map, destructor_function);
+
+    if (k >= 0) {
+        *key = k;
+        err  = 0;
+    }
+    tlsmap_unlock(map);
+    return err;
+}
+
+
+/* This deletes a pthread_key_t. note that the standard mandates that this does
+ * not call the destructor of non-NULL key values. Instead, it is the
+ * responsibility of the caller to properly dispose of the corresponding data
+ * and resources, using any means it finds suitable.
+ *
+ * On the other hand, this function will clear the corresponding key data
+ * values in all known threads. this prevents later (invalid) calls to
+ * pthread_getspecific() to receive invalid/stale values.
+ */
+int pthread_key_delete(pthread_key_t key)
+{
+    uint32_t             err;
+    pthread_internal_t*  thr;
+    tlsmap_t*            map;
+
+    if (!TLSMAP_VALIDATE_KEY(key)) {
+        return EINVAL;
+    }
+
+    map = tlsmap_lock();
+
+    if (!tlsmap_test(map, key)) {
+        err = EINVAL;
+        goto err1;
+    }
+
+    /* clear value in all threads */
+    pthread_mutex_lock(&gThreadListLock);
+    for ( thr = gThreadList; thr != NULL; thr = thr->next ) {
+        /* avoid zombie threads with a negative 'join_count'. these are really
+         * already dead and don't have a TLS area anymore.
+         *
+         * similarly, it is possible to have thr->tls == NULL for threads that
+         * were just recently created through pthread_create() but whose
+         * startup trampoline (__thread_entry) hasn't been run yet by the
+         * scheduler. thr->tls will also be NULL after it's stack has been
+         * unmapped but before the ongoing pthread_join() is finished.
+         * so check for this too.
+         */
+        if (thr->join_count < 0 || !thr->tls)
+            continue;
+
+        thr->tls[key] = NULL;
+    }
+    tlsmap_clear(map, key);
+
+    pthread_mutex_unlock(&gThreadListLock);
+    err = 0;
+
+err1:
+    tlsmap_unlock(map);
+    return err;
+}
+
+
+int pthread_setspecific(pthread_key_t key, const void *ptr)
+{
+    int        err = EINVAL;
+    tlsmap_t*  map;
+
+    if (TLSMAP_VALIDATE_KEY(key)) {
+        /* check that we're trying to set data for an allocated key */
+        map = tlsmap_lock();
+        if (tlsmap_test(map, key)) {
+            ((uint32_t *)__get_tls())[key] = (uint32_t)ptr;
+            err = 0;
+        }
+        tlsmap_unlock(map);
+    }
+    return err;
+}
+
+void * pthread_getspecific(pthread_key_t key)
+{
+    if (!TLSMAP_VALIDATE_KEY(key)) {
+        return NULL;
+    }
+
+    /* for performance reason, we do not lock/unlock the global TLS map
+     * to check that the key is properly allocated. if the key was not
+     * allocated, the value read from the TLS should always be NULL
+     * due to pthread_key_delete() clearing the values for all threads.
+     */
+    return (void *)(((unsigned *)__get_tls())[key]);
+}
+
+/* Posix mandates that this be defined in <limits.h> but we don't have
+ * it just yet.
+ */
+#ifndef PTHREAD_DESTRUCTOR_ITERATIONS
+#  define PTHREAD_DESTRUCTOR_ITERATIONS  4
+#endif
+
+/* this function is called from pthread_exit() to remove all TLS key data
+ * from this thread's TLS area. this must call the destructor of all keys
+ * that have a non-NULL data value (and a non-NULL destructor).
+ *
+ * because destructors can do funky things like deleting/creating other
+ * keys, we need to implement this in a loop
+ */
+static void pthread_key_clean_all(void)
+{
+    tlsmap_t*    map;
+    void**       tls = (void**)__get_tls();
+    int          rounds = PTHREAD_DESTRUCTOR_ITERATIONS;
+
+    map = tlsmap_lock();
+
+    for (rounds = PTHREAD_DESTRUCTOR_ITERATIONS; rounds > 0; rounds--)
+    {
+        int  kk, count = 0;
+
+        for (kk = TLSMAP_START; kk < TLSMAP_SIZE; kk++) {
+            if ( tlsmap_test(map, kk) )
+            {
+                void*       data = tls[kk];
+                tls_dtor_t  dtor = map->dtors[kk];
+
+                if (data != NULL && dtor != NULL)
+                {
+                   /* we need to clear the key data now, this will prevent the
+                    * destructor (or a later one) from seeing the old value if
+                    * it calls pthread_getspecific() for some odd reason
+                    *
+                    * we do not do this if 'dtor == NULL' just in case another
+                    * destructor function might be responsible for manually
+                    * releasing the corresponding data.
+                    */
+                    tls[kk] = NULL;
+
+                   /* because the destructor is free to call pthread_key_create
+                    * and/or pthread_key_delete, we need to temporarily unlock
+                    * the TLS map
+                    */
+                    tlsmap_unlock(map);
+                    (*dtor)(data);
+                    map = tlsmap_lock();
+
+                    count += 1;
+                }
+            }
+        }
+
+        /* if we didn't call any destructor, there is no need to check the
+         * TLS data again
+         */
+        if (count == 0)
+            break;
+    }
+    tlsmap_unlock(map);
+}
+
 // man says this should be in <linux/unistd.h>, but it isn't
 extern int tgkill(int tgid, int tid, int sig);
 
diff --git a/libc/bionic/pthread_internal.h b/libc/bionic/pthread_internal.h
index 24b420c..bc68291 100644
--- a/libc/bionic/pthread_internal.h
+++ b/libc/bionic/pthread_internal.h
@@ -60,11 +60,6 @@
 void _pthread_internal_add( pthread_internal_t*  thread );
 pthread_internal_t* __get_thread(void);
 
-__LIBC_HIDDEN__ void pthread_key_clean_all(void);
-
-extern pthread_internal_t* gThreadList;
-extern pthread_mutex_t gThreadListLock;
-
 /* needed by posix-timers.c */
 
 static __inline__ void timespec_add( struct timespec*  a, const struct timespec*  b )
diff --git a/libc/bionic/pthread_key.cpp b/libc/bionic/pthread_key.cpp
deleted file mode 100644
index 00dacba..0000000
--- a/libc/bionic/pthread_key.cpp
+++ /dev/null
@@ -1,280 +0,0 @@
-/*
- * Copyright (C) 2008 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include <assert.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <limits.h>
-#include <malloc.h>
-#include <memory.h>
-#include <pthread.h>
-#include <signal.h>
-#include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <sys/atomics.h>
-#include <sys/mman.h>
-#include <sys/prctl.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <time.h>
-#include <unistd.h>
-
-#include "bionic_atomic_inline.h"
-#include "bionic_futex.h"
-#include "bionic_pthread.h"
-#include "bionic_ssp.h"
-#include "bionic_tls.h"
-#include "debug_format.h"
-#include "pthread_internal.h"
-#include "thread_private.h"
-
-/* A technical note regarding our thread-local-storage (TLS) implementation:
- *
- * There can be up to BIONIC_TLS_SLOTS independent TLS keys in a given process,
- * The keys below TLS_SLOT_FIRST_USER_SLOT are reserved for Bionic to hold
- * special thread-specific variables like errno or a pointer to
- * the current thread's descriptor. These entries cannot be accessed through
- * pthread_getspecific() / pthread_setspecific() or pthread_key_delete()
- *
- * The 'tls_map_t' type defined below implements a shared global map of
- * currently created/allocated TLS keys and the destructors associated
- * with them.
- *
- * The global TLS map simply contains a bitmap of allocated keys, and
- * an array of destructors.
- *
- * Each thread has a TLS area that is a simple array of BIONIC_TLS_SLOTS void*
- * pointers. the TLS area of the main thread is stack-allocated in
- * __libc_init_common, while the TLS area of other threads is placed at
- * the top of their stack in pthread_create.
- *
- * When pthread_key_delete() is called it will erase the key's bitmap bit
- * and its destructor, and will also clear the key data in the TLS area of
- * all created threads. As mandated by Posix, it is the responsibility of
- * the caller of pthread_key_delete() to properly reclaim the objects that
- * were pointed to by these data fields (either before or after the call).
- */
-
-#define TLSMAP_BITS       32
-#define TLSMAP_WORDS      ((BIONIC_TLS_SLOTS+TLSMAP_BITS-1)/TLSMAP_BITS)
-#define TLSMAP_WORD(m,k)  (m).map[(k)/TLSMAP_BITS]
-#define TLSMAP_MASK(k)    (1U << ((k)&(TLSMAP_BITS-1)))
-
-static inline bool IsValidUserKey(pthread_key_t key) {
-  return (key >= TLS_SLOT_FIRST_USER_SLOT && key < BIONIC_TLS_SLOTS);
-}
-
-typedef void (*key_destructor_t)(void*);
-
-struct tls_map_t {
-  bool is_initialized;
-
-  /* bitmap of allocated keys */
-  uint32_t map[TLSMAP_WORDS];
-
-  key_destructor_t key_destructors[BIONIC_TLS_SLOTS];
-};
-
-class ScopedTlsMapAccess {
- public:
-  ScopedTlsMapAccess() {
-    Lock();
-
-    // If this is the first time the TLS map has been accessed,
-    // mark the slots belonging to well-known keys as being in use.
-    // This isn't currently necessary because the well-known keys
-    // can only be accessed directly by bionic itself, do not have
-    // destructors, and all the functions that touch the TLS map
-    // start after the maximum well-known slot.
-    if (!s_tls_map_.is_initialized) {
-      for (pthread_key_t key = 0; key < TLS_SLOT_FIRST_USER_SLOT; ++key) {
-        SetInUse(key, NULL);
-      }
-      s_tls_map_.is_initialized = true;
-    }
-  }
-
-  ~ScopedTlsMapAccess() {
-    Unlock();
-  }
-
-  int CreateKey(pthread_key_t* result, void (*key_destructor)(void*)) {
-    // Take the first unallocated key.
-    for (int key = 0; key < BIONIC_TLS_SLOTS; ++key) {
-      if (!IsInUse(key)) {
-        SetInUse(key, key_destructor);
-        *result = key;
-        return 0;
-      }
-    }
-
-    // We hit PTHREAD_KEYS_MAX. POSIX says EAGAIN for this case.
-    return EAGAIN;
-  }
-
-  void DeleteKey(pthread_key_t key) {
-    TLSMAP_WORD(s_tls_map_, key) &= ~TLSMAP_MASK(key);
-    s_tls_map_.key_destructors[key] = NULL;
-  }
-
-  bool IsInUse(pthread_key_t key) {
-    return (TLSMAP_WORD(s_tls_map_, key) & TLSMAP_MASK(key)) != 0;
-  }
-
-  void SetInUse(pthread_key_t key, void (*key_destructor)(void*)) {
-    TLSMAP_WORD(s_tls_map_, key) |= TLSMAP_MASK(key);
-    s_tls_map_.key_destructors[key] = key_destructor;
-  }
-
-  // Called from pthread_exit() to remove all TLS key data
-  // from this thread's TLS area. This must call the destructor of all keys
-  // that have a non-NULL data value and a non-NULL destructor.
-  void CleanAll() {
-    void** tls = (void**)__get_tls();
-
-    // Because destructors can do funky things like deleting/creating other
-    // keys, we need to implement this in a loop.
-    for (int rounds = PTHREAD_DESTRUCTOR_ITERATIONS; rounds > 0; --rounds) {
-      size_t called_destructor_count = 0;
-      for (int key = 0; key < BIONIC_TLS_SLOTS; ++key) {
-        if (IsInUse(key)) {
-          void* data = tls[key];
-          void (*key_destructor)(void*) = s_tls_map_.key_destructors[key];
-
-          if (data != NULL && key_destructor != NULL) {
-            // we need to clear the key data now, this will prevent the
-            // destructor (or a later one) from seeing the old value if
-            // it calls pthread_getspecific() for some odd reason
-
-            // we do not do this if 'key_destructor == NULL' just in case another
-            // destructor function might be responsible for manually
-            // releasing the corresponding data.
-            tls[key] = NULL;
-
-            // because the destructor is free to call pthread_key_create
-            // and/or pthread_key_delete, we need to temporarily unlock
-            // the TLS map
-            Unlock();
-            (*key_destructor)(data);
-            Lock();
-            ++called_destructor_count;
-          }
-        }
-      }
-
-      // If we didn't call any destructors, there is no need to check the TLS data again.
-      if (called_destructor_count == 0) {
-        break;
-      }
-    }
-  }
-
- private:
-  static tls_map_t s_tls_map_;
-  static pthread_mutex_t s_tls_map_lock_;
-
-  void Lock() {
-    pthread_mutex_lock(&s_tls_map_lock_);
-  }
-
-  void Unlock() {
-    pthread_mutex_unlock(&s_tls_map_lock_);
-  }
-};
-
-tls_map_t ScopedTlsMapAccess::s_tls_map_;
-pthread_mutex_t ScopedTlsMapAccess::s_tls_map_lock_;
-
-__LIBC_HIDDEN__ void pthread_key_clean_all() {
-  ScopedTlsMapAccess tls_map;
-  tls_map.CleanAll();
-}
-
-int pthread_key_create(pthread_key_t* key, void (*key_destructor)(void*)) {
-  ScopedTlsMapAccess tls_map;
-  return tls_map.CreateKey(key, key_destructor);
-}
-
-// Deletes a pthread_key_t. note that the standard mandates that this does
-// not call the destructors for non-NULL key values. Instead, it is the
-// responsibility of the caller to properly dispose of the corresponding data
-// and resources, using any means it finds suitable.
-int pthread_key_delete(pthread_key_t key) {
-  ScopedTlsMapAccess tls_map;
-
-  if (!IsValidUserKey(key) || !tls_map.IsInUse(key)) {
-    return EINVAL;
-  }
-
-  // Clear value in all threads.
-  pthread_mutex_lock(&gThreadListLock);
-  for (pthread_internal_t*  t = gThreadList; t != NULL; t = t->next) {
-    // Avoid zombie threads with a negative 'join_count'. These are really
-    // already dead and don't have a TLS area anymore.
-
-    // Similarly, it is possible to have t->tls == NULL for threads that
-    // were just recently created through pthread_create() but whose
-    // startup trampoline (__thread_entry) hasn't been run yet by the
-    // scheduler. t->tls will also be NULL after it's stack has been
-    // unmapped but before the ongoing pthread_join() is finished.
-    // so check for this too.
-    if (t->join_count < 0 || !t->tls) {
-      continue;
-    }
-
-    t->tls[key] = NULL;
-  }
-  tls_map.DeleteKey(key);
-
-  pthread_mutex_unlock(&gThreadListLock);
-  return 0;
-}
-
-void* pthread_getspecific(pthread_key_t key) {
-  if (!IsValidUserKey(key)) {
-    return NULL;
-  }
-
-  // For performance reasons, we do not lock/unlock the global TLS map
-  // to check that the key is properly allocated. If the key was not
-  // allocated, the value read from the TLS should always be NULL
-  // due to pthread_key_delete() clearing the values for all threads.
-  return (void *)(((unsigned *)__get_tls())[key]);
-}
-
-int pthread_setspecific(pthread_key_t key, const void* ptr) {
-  ScopedTlsMapAccess tls_map;
-
-  if (!IsValidUserKey(key) || !tls_map.IsInUse(key)) {
-    return EINVAL;
-  }
-
-  ((uint32_t *)__get_tls())[key] = (uint32_t)ptr;
-  return 0;
-}
diff --git a/libc/bionic/sysconf.cpp b/libc/bionic/sysconf.cpp
index f4845e1..6555a66 100644
--- a/libc/bionic/sysconf.cpp
+++ b/libc/bionic/sysconf.cpp
@@ -55,6 +55,7 @@
 
 /* the following depends on our implementation */
 #define  SYSTEM_ATEXIT_MAX          65536    /* our implementation is unlimited */
+#define  SYSTEM_THREAD_KEYS_MAX     BIONIC_TLS_SLOTS
 #define  SYSTEM_THREAD_STACK_MIN    32768    /* lower values may be possible, but be conservative */
 #define  SYSTEM_THREAD_THREADS_MAX  2048     /* really unlimited */
 
@@ -301,13 +302,10 @@
     // GETPW_R_SIZE_MAX ?
 
     case _SC_LOGIN_NAME_MAX:    return SYSTEM_LOGIN_NAME_MAX;
-
-    case _SC_THREAD_DESTRUCTOR_ITERATIONS:
-      return _POSIX_THREAD_DESTRUCTOR_ITERATIONS;
-
-    case _SC_THREAD_KEYS_MAX:
-      return (BIONIC_TLS_SLOTS - TLS_SLOT_FIRST_USER_SLOT);
-
+#ifdef _POSIX_THREAD_DESTRUCTOR_ITERATIONS
+    case _SC_THREAD_DESTRUCTOR_ITERATIONS:  return _POSIX_THREAD_DESTRUCTOR_ITERATIONS;
+#endif
+    case _SC_THREAD_KEYS_MAX:     return SYSTEM_THREAD_KEYS_MAX;
     case _SC_THREAD_STACK_MIN:    return SYSTEM_THREAD_STACK_MIN;
     case _SC_THREAD_THREADS_MAX:  return SYSTEM_THREAD_THREADS_MAX;
     case _SC_TTY_NAME_MAX:        return SYSTEM_TTY_NAME_MAX;