diff --git a/nptl/sysdeps/unix/sysv/linux/i386/bits/pthreadtypes.h b/nptl/sysdeps/unix/sysv/linux/i386/bits/pthreadtypes.h
index 2341a9c650..662f3e54a8 100644
--- a/nptl/sysdeps/unix/sysv/linux/i386/bits/pthreadtypes.h
+++ b/nptl/sysdeps/unix/sysv/linux/i386/bits/pthreadtypes.h
@@ -56,7 +56,7 @@ typedef union
        binary compatibility.  */
     int __kind;
     unsigned int __nusers;
-    union
+    __extension__ union
     {
       int __spins;
       struct __pthread_mutex_s *__next;
diff --git a/nptl/sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h b/nptl/sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h
index 56ffef3d0b..493c2ab557 100644
--- a/nptl/sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h
+++ b/nptl/sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h
@@ -80,7 +80,7 @@ typedef union
 # define __PTHREAD_MUTEX_HAVE_PREV	1
 #else
     unsigned int __nusers;
-    union
+    __extension__ union
     {
       int __spins;
       struct __pthread_mutex_s *__next;
diff --git a/nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h b/nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h
index a2ad05dd54..df8beeb685 100644
--- a/nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h
+++ b/nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h
@@ -79,7 +79,7 @@ typedef union
 # define __PTHREAD_MUTEX_HAVE_PREV	1
 #else
     unsigned int __nusers;
-    union
+    __extension__ union
     {
       int __spins;
       struct __pthread_mutex_s *__next;
diff --git a/nptl/sysdeps/unix/sysv/linux/sh/bits/pthreadtypes.h b/nptl/sysdeps/unix/sysv/linux/sh/bits/pthreadtypes.h
index 727ab811c0..211c3fb08e 100644
--- a/nptl/sysdeps/unix/sysv/linux/sh/bits/pthreadtypes.h
+++ b/nptl/sysdeps/unix/sysv/linux/sh/bits/pthreadtypes.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -57,7 +57,7 @@ typedef union __pthread_mutex_u
        binary compatibility.  */
     int __kind;
     unsigned int __nusers;
-    union
+    __extension__ union
     {
       int __spins;
       union __pthread_mutex_u *__next;
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/bits/pthreadtypes.h b/nptl/sysdeps/unix/sysv/linux/x86_64/bits/pthreadtypes.h
index ba940b35e0..81942bc86c 100644
--- a/nptl/sysdeps/unix/sysv/linux/x86_64/bits/pthreadtypes.h
+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/bits/pthreadtypes.h
@@ -79,7 +79,7 @@ typedef union
 # define __PTHREAD_MUTEX_HAVE_PREV	1
 #else
     unsigned int __nusers;
-    union
+    __extension__ union
     {
       int __spins;
       struct __pthread_mutex_s *__next;