diff --git a/ChangeLog b/ChangeLog
index 09e25be..203f014 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,72 @@
 2017-10-25  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
+	[BZ #22298]
+	* nptl/allocatestack.c (allocate_stack): Check if
+	__PTHREAD_MUTEX_HAVE_PREV is non-zero, instead if
+	__PTHREAD_MUTEX_HAVE_PREV is defined.
+	* nptl/descr.h (pthread): Likewise.
+	* nptl/nptl-init.c (__pthread_initialize_minimal_internal):
+	Likewise.
+	* nptl/pthread_create.c (START_THREAD_DEFN): Likewise.
+	* sysdeps/nptl/fork.c (__libc_fork): Likewise.
+	* sysdeps/nptl/pthread.h (PTHREAD_MUTEX_INITIALIZER): Likewise.
+	* sysdeps/nptl/bits/thread-shared-types.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	(__pthread_internal_list): Check __PTHREAD_MUTEX_USE_UNION instead
+	of __WORDSIZE for internal layout.
+	(__pthread_mutex_s): Check __PTHREAD_MUTEX_NUSERS_AFTER_KIND instead
+	of __WORDSIZE for internal __nusers layout and __PTHREAD_MUTEX_USE_UNION
+	instead of __WORDSIZE whether to use an union for __spins and __list
+	fields.
+	(__PTHREAD_MUTEX_HAVE_PREV): Define also for __PTHREAD_MUTEX_USE_UNION
+	case.
+	* sysdeps/aarch64/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/alpha/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/arm/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/hppa/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/ia64/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/m68k/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/microblaze/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/mips/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/nios2/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/powerpc/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/s390/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/sh/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/sparc/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/tile/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+	* sysdeps/x86/nptl/bits/pthreadtypes-arch.h
+	(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
+	defines.
+
 	* nptl/pthreadP.h (ASSERT_TYPE_SIZE, ASSERT_PTHREAD_INTERNAL_SIZE):
 	New macros.
 	* nptl/pthread_attr_init.c (__pthread_mutex_init): Add build time
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index ad9add8..1cc7893 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -753,7 +753,7 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp,
 				  - offsetof (pthread_mutex_t,
 					      __data.__list.__next));
   pd->robust_head.list_op_pending = NULL;
-#ifdef __PTHREAD_MUTEX_HAVE_PREV
+#if __PTHREAD_MUTEX_HAVE_PREV
   pd->robust_prev = &pd->robust_head;
 #endif
   pd->robust_head.list = &pd->robust_head;
diff --git a/nptl/descr.h b/nptl/descr.h
index c5ad0c8..c83b17b 100644
--- a/nptl/descr.h
+++ b/nptl/descr.h
@@ -169,7 +169,7 @@ struct pthread
   pid_t pid_ununsed;
 
   /* List of robust mutexes the thread is holding.  */
-#ifdef __PTHREAD_MUTEX_HAVE_PREV
+#if __PTHREAD_MUTEX_HAVE_PREV
   void *robust_prev;
   struct robust_list_head robust_head;
 
diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c
index 2921607..869e926 100644
--- a/nptl/nptl-init.c
+++ b/nptl/nptl-init.c
@@ -297,7 +297,7 @@ __pthread_initialize_minimal_internal (void)
 
   /* Initialize the robust mutex data.  */
   {
-#ifdef __PTHREAD_MUTEX_HAVE_PREV
+#if __PTHREAD_MUTEX_HAVE_PREV
     pd->robust_prev = &pd->robust_head;
 #endif
     pd->robust_head.list = &pd->robust_head;
diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
index 992331e..51ae60d 100644
--- a/nptl/pthread_create.c
+++ b/nptl/pthread_create.c
@@ -518,7 +518,7 @@ START_THREAD_DEFN
 
 #ifndef __ASSUME_SET_ROBUST_LIST
   /* If this thread has any robust mutexes locked, handle them now.  */
-# ifdef __PTHREAD_MUTEX_HAVE_PREV
+# if __PTHREAD_MUTEX_HAVE_PREV
   void *robust = pd->robust_head.list;
 # else
   __pthread_slist_t *robust = pd->robust_list.__next;
@@ -536,7 +536,7 @@ START_THREAD_DEFN
 					 __list.__next));
 	  robust = *((void **) robust);
 
-# ifdef __PTHREAD_MUTEX_HAVE_PREV
+# if __PTHREAD_MUTEX_HAVE_PREV
 	  this->__list.__prev = NULL;
 # endif
 	  this->__list.__next = NULL;
diff --git a/sysdeps/aarch64/nptl/bits/pthreadtypes-arch.h b/sysdeps/aarch64/nptl/bits/pthreadtypes-arch.h
index d13a75d..9ab23d0 100644
--- a/sysdeps/aarch64/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/aarch64/nptl/bits/pthreadtypes-arch.h
@@ -45,6 +45,8 @@
 #define __PTHREAD_COMPAT_PADDING_MID
 #define __PTHREAD_COMPAT_PADDING_END
 #define __PTHREAD_MUTEX_LOCK_ELISION	0
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  0
+#define __PTHREAD_MUTEX_USE_UNION          0
 
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
diff --git a/sysdeps/alpha/nptl/bits/pthreadtypes-arch.h b/sysdeps/alpha/nptl/bits/pthreadtypes-arch.h
index b6f6cb1..429df10 100644
--- a/sysdeps/alpha/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/alpha/nptl/bits/pthreadtypes-arch.h
@@ -33,6 +33,8 @@
 #define __PTHREAD_COMPAT_PADDING_MID
 #define __PTHREAD_COMPAT_PADDING_END
 #define __PTHREAD_MUTEX_LOCK_ELISION    0
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  0
+#define __PTHREAD_MUTEX_USE_UNION          0
 
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
diff --git a/sysdeps/arm/nptl/bits/pthreadtypes-arch.h b/sysdeps/arm/nptl/bits/pthreadtypes-arch.h
index 3f9eca4..3911c81 100644
--- a/sysdeps/arm/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/arm/nptl/bits/pthreadtypes-arch.h
@@ -34,6 +34,8 @@
 #define __PTHREAD_COMPAT_PADDING_MID
 #define __PTHREAD_COMPAT_PADDING_END
 #define __PTHREAD_MUTEX_LOCK_ELISION    0
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  1
+#define __PTHREAD_MUTEX_USE_UNION          1
 
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
diff --git a/sysdeps/hppa/nptl/bits/pthreadtypes-arch.h b/sysdeps/hppa/nptl/bits/pthreadtypes-arch.h
index c158562..865a14e 100644
--- a/sysdeps/hppa/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/hppa/nptl/bits/pthreadtypes-arch.h
@@ -48,6 +48,8 @@
    pthread_mutex_t is larger than Linuxthreads.  */
 #define __PTHREAD_COMPAT_PADDING_END  int __reserved[2];
 #define __PTHREAD_MUTEX_LOCK_ELISION    0
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  1
+#define __PTHREAD_MUTEX_USE_UNION          1
 
 #define __LOCK_ALIGNMENT __attribute__ ((__aligned__(16)))
 #define __ONCE_ALIGNMENT
diff --git a/sysdeps/ia64/nptl/bits/pthreadtypes-arch.h b/sysdeps/ia64/nptl/bits/pthreadtypes-arch.h
index 631cb33..2a3bc75 100644
--- a/sysdeps/ia64/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/ia64/nptl/bits/pthreadtypes-arch.h
@@ -33,6 +33,8 @@
 #define __PTHREAD_COMPAT_PADDING_MID
 #define __PTHREAD_COMPAT_PADDING_END
 #define __PTHREAD_MUTEX_LOCK_ELISION    0
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  0
+#define __PTHREAD_MUTEX_USE_UNION          0
 
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
diff --git a/sysdeps/m68k/nptl/bits/pthreadtypes-arch.h b/sysdeps/m68k/nptl/bits/pthreadtypes-arch.h
index 845b9e6..966cc75 100644
--- a/sysdeps/m68k/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/m68k/nptl/bits/pthreadtypes-arch.h
@@ -35,6 +35,8 @@
 #define __PTHREAD_COMPAT_PADDING_MID
 #define __PTHREAD_COMPAT_PADDING_END
 #define __PTHREAD_MUTEX_LOCK_ELISION    0
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  1
+#define __PTHREAD_MUTEX_USE_UNION          1
 
 #define __LOCK_ALIGNMENT __attribute__ ((__aligned__ (4)))
 #define __ONCE_ALIGNMENT __attribute__ ((__aligned__ (4)))
diff --git a/sysdeps/microblaze/nptl/bits/pthreadtypes-arch.h b/sysdeps/microblaze/nptl/bits/pthreadtypes-arch.h
index d687e2c..e44f2dc 100644
--- a/sysdeps/microblaze/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/microblaze/nptl/bits/pthreadtypes-arch.h
@@ -35,6 +35,8 @@
 #define __PTHREAD_COMPAT_PADDING_MID
 #define __PTHREAD_COMPAT_PADDING_END
 #define __PTHREAD_MUTEX_LOCK_ELISION    0
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  1
+#define __PTHREAD_MUTEX_USE_UNION          1
 
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
diff --git a/sysdeps/mips/nptl/bits/pthreadtypes-arch.h b/sysdeps/mips/nptl/bits/pthreadtypes-arch.h
index 6aa1bda..f03389a 100644
--- a/sysdeps/mips/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/mips/nptl/bits/pthreadtypes-arch.h
@@ -42,6 +42,8 @@
 #define __PTHREAD_COMPAT_PADDING_MID
 #define __PTHREAD_COMPAT_PADDING_END
 #define __PTHREAD_MUTEX_LOCK_ELISION    0
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  (_MIPS_SIM != _ABI64)
+#define __PTHREAD_MUTEX_USE_UNION          (_MIPS_SIM != _ABI64)
 
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
diff --git a/sysdeps/nios2/nptl/bits/pthreadtypes-arch.h b/sysdeps/nios2/nptl/bits/pthreadtypes-arch.h
index e2732f9..83f8684 100644
--- a/sysdeps/nios2/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/nios2/nptl/bits/pthreadtypes-arch.h
@@ -35,6 +35,8 @@
 #define __PTHREAD_COMPAT_PADDING_MID
 #define __PTHREAD_COMPAT_PADDING_END
 #define __PTHREAD_MUTEX_LOCK_ELISION    0
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  1
+#define __PTHREAD_MUTEX_USE_UNION          1
 
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
diff --git a/sysdeps/nptl/bits/thread-shared-types.h b/sysdeps/nptl/bits/thread-shared-types.h
index 68b82b6..da4358a 100644
--- a/sysdeps/nptl/bits/thread-shared-types.h
+++ b/sysdeps/nptl/bits/thread-shared-types.h
@@ -42,6 +42,25 @@
 				    the internal structure.
    __PTHREAD_MUTEX_LOCK_ELISION   - 1 if the architecture supports lock
 				    elision or 0 otherwise.
+   __PTHREAD_MUTEX_NUSERS_AFTER_KIND - control where to put __nusers.  The
+				       preferred value for new architectures
+				       is 0.
+   __PTHREAD_MUTEX_USE_UNION      - control whether internal __spins and
+				    __list will be place inside a union for
+				    linuxthreads compatibility.
+				    The preferred value for new architectures
+				    is 0.
+
+   For a new port the preferred values for the required defines are:
+
+   #define __PTHREAD_COMPAT_PADDING_MID
+   #define __PTHREAD_COMPAT_PADDING_END
+   #define __PTHREAD_MUTEX_LOCK_ELISION         0
+   #define __PTHREAD_MUTEX_NUSERS_AFTER_KIND    0
+   #define __PTHREAD_MUTEX_USE_UNION            0
+
+   __PTHREAD_MUTEX_LOCK_ELISION can be set to 1 if the hardware plans to
+   eventually support lock elision using transactional memory.
 
    The additional macro defines any constraint for the lock alignment
    inside the thread structures:
@@ -59,7 +78,7 @@
 
 /* Common definition of pthread_mutex_t. */
 
-#if __WORDSIZE == 64
+#if !__PTHREAD_MUTEX_USE_UNION
 typedef struct __pthread_internal_list
 {
   struct __pthread_internal_list *__prev;
@@ -74,7 +93,7 @@ typedef struct __pthread_internal_slist
 
 /* Lock elision support.  */
 #if __PTHREAD_MUTEX_LOCK_ELISION
-# if __WORDSIZE == 64
+# if !__PTHREAD_MUTEX_USE_UNION
 #  define __PTHREAD_SPINS_DATA	\
   short __spins;		\
   short __elision
@@ -101,24 +120,27 @@ struct __pthread_mutex_s
   int __lock __LOCK_ALIGNMENT;
   unsigned int __count;
   int __owner;
-#if __WORDSIZE == 64
+#if !__PTHREAD_MUTEX_NUSERS_AFTER_KIND
   unsigned int __nusers;
 #endif
   /* KIND must stay at this position in the structure to maintain
      binary compatibility with static initializers.  */
   int __kind;
   __PTHREAD_COMPAT_PADDING_MID
-#if __WORDSIZE == 64
+#if __PTHREAD_MUTEX_NUSERS_AFTER_KIND
+  unsigned int __nusers;
+#endif
+#if !__PTHREAD_MUTEX_USE_UNION
   __PTHREAD_SPINS_DATA;
   __pthread_list_t __list;
 # define __PTHREAD_MUTEX_HAVE_PREV      1
 #else
-  unsigned int __nusers;
   __extension__ union
   {
     __PTHREAD_SPINS_DATA;
     __pthread_slist_t __list;
   };
+# define __PTHREAD_MUTEX_HAVE_PREV      0
 #endif
   __PTHREAD_COMPAT_PADDING_END
 };
diff --git a/sysdeps/nptl/fork.c b/sysdeps/nptl/fork.c
index 4bb87e2..48676c2 100644
--- a/sysdeps/nptl/fork.c
+++ b/sysdeps/nptl/fork.c
@@ -166,7 +166,7 @@ __libc_fork (void)
 	 inherit the correct value from the parent.  We do not need to clear
 	 the pending operation because it must have been zero when fork was
 	 called.  */
-# ifdef __PTHREAD_MUTEX_HAVE_PREV
+# if __PTHREAD_MUTEX_HAVE_PREV
       self->robust_prev = &self->robust_head;
 # endif
       self->robust_head.list = &self->robust_head;
diff --git a/sysdeps/nptl/pthread.h b/sysdeps/nptl/pthread.h
index 632ea7b..2b2b386 100644
--- a/sysdeps/nptl/pthread.h
+++ b/sysdeps/nptl/pthread.h
@@ -83,7 +83,7 @@ enum
 #endif
 
 
-#ifdef __PTHREAD_MUTEX_HAVE_PREV
+#if __PTHREAD_MUTEX_HAVE_PREV
 # define PTHREAD_MUTEX_INITIALIZER \
   { { 0, 0, 0, 0, 0, __PTHREAD_SPINS, { 0, 0 } } }
 # ifdef __USE_GNU
diff --git a/sysdeps/powerpc/nptl/bits/pthreadtypes-arch.h b/sysdeps/powerpc/nptl/bits/pthreadtypes-arch.h
index f29119b..8158cb5 100644
--- a/sysdeps/powerpc/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/powerpc/nptl/bits/pthreadtypes-arch.h
@@ -42,6 +42,8 @@
 #define __PTHREAD_COMPAT_PADDING_MID
 #define __PTHREAD_COMPAT_PADDING_END
 #define __PTHREAD_MUTEX_LOCK_ELISION    1
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  (__WORDSIZE != 64)
+#define __PTHREAD_MUTEX_USE_UNION          (__WORDSIZE != 64)
 
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
diff --git a/sysdeps/s390/nptl/bits/pthreadtypes-arch.h b/sysdeps/s390/nptl/bits/pthreadtypes-arch.h
index 3a9ac57..1ae2773 100644
--- a/sysdeps/s390/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/s390/nptl/bits/pthreadtypes-arch.h
@@ -45,6 +45,8 @@
 #else
 #define __PTHREAD_MUTEX_LOCK_ELISION	0
 #endif
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  (__WORDSIZE != 64)
+#define __PTHREAD_MUTEX_USE_UNION          (__WORDSIZE != 64)
 
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
diff --git a/sysdeps/sh/nptl/bits/pthreadtypes-arch.h b/sysdeps/sh/nptl/bits/pthreadtypes-arch.h
index b2615fe..e707751 100644
--- a/sysdeps/sh/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/sh/nptl/bits/pthreadtypes-arch.h
@@ -34,6 +34,8 @@
 #define __PTHREAD_COMPAT_PADDING_MID
 #define __PTHREAD_COMPAT_PADDING_END
 #define __PTHREAD_MUTEX_LOCK_ELISION    0
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  1
+#define __PTHREAD_MUTEX_USE_UNION          1
 
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
diff --git a/sysdeps/sparc/nptl/bits/pthreadtypes-arch.h b/sysdeps/sparc/nptl/bits/pthreadtypes-arch.h
index 1e188cf..0f96f37 100644
--- a/sysdeps/sparc/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/sparc/nptl/bits/pthreadtypes-arch.h
@@ -43,6 +43,8 @@
 #define __PTHREAD_COMPAT_PADDING_MID
 #define __PTHREAD_COMPAT_PADDING_END
 #define __PTHREAD_MUTEX_LOCK_ELISION    0
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  (__WORDSIZE != 64)
+#define __PTHREAD_MUTEX_USE_UNION          (__WORDSIZE != 64)
 
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
diff --git a/sysdeps/tile/nptl/bits/pthreadtypes-arch.h b/sysdeps/tile/nptl/bits/pthreadtypes-arch.h
index 145ee42..054474f 100644
--- a/sysdeps/tile/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/tile/nptl/bits/pthreadtypes-arch.h
@@ -43,6 +43,8 @@
 #define __PTHREAD_COMPAT_PADDING_MID
 #define __PTHREAD_COMPAT_PADDING_END
 #define __PTHREAD_MUTEX_LOCK_ELISION    0
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  (__WORDSIZE != 64)
+#define __PTHREAD_MUTEX_USE_UNION          (__WORDSIZE != 64)
 
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
diff --git a/sysdeps/x86/nptl/bits/pthreadtypes-arch.h b/sysdeps/x86/nptl/bits/pthreadtypes-arch.h
index fd86806..74d5f6d 100644
--- a/sysdeps/x86/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/x86/nptl/bits/pthreadtypes-arch.h
@@ -51,6 +51,13 @@
 #define __PTHREAD_COMPAT_PADDING_MID
 #define __PTHREAD_COMPAT_PADDING_END
 #define __PTHREAD_MUTEX_LOCK_ELISION    1
+#ifdef __x86_64__
+# define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  0
+# define __PTHREAD_MUTEX_USE_UNION          0
+#else
+# define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  1
+# define __PTHREAD_MUTEX_USE_UNION          1
+#endif
 
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
