commit 59eda029a8a35e5f4e5cd7be0f84c6629e48ec6e
Author: Florian Weimer <fweimer@redhat.com>
Date:   Fri Feb 19 17:07:45 2016 +0100

    malloc: Remove NO_THREADS
    
    No functional change.  It was not possible to build without
    threading support before.

Index: b/malloc/arena.c
===================================================================
--- a/malloc/arena.c
+++ b/malloc/arena.c
@@ -135,8 +135,6 @@ int __malloc_initialized = -1;
 
 /**************************************************************************/
 
-#ifndef NO_THREADS
-
 /* atfork support.  */
 
 static void *(*save_malloc_hook)(size_t __size, const void *);
@@ -341,7 +339,6 @@ ptmalloc_unlock_all2 (void)
 
 #  define ptmalloc_unlock_all2 ptmalloc_unlock_all
 # endif
-#endif  /* !NO_THREADS */
 
 /* Initialization routine. */
 #include <string.h>
Index: b/malloc/malloc.c
===================================================================
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -1074,10 +1074,8 @@ static void*   realloc_check(void* oldme
 			       const void *caller);
 static void*   memalign_check(size_t alignment, size_t bytes,
 				const void *caller);
-#ifndef NO_THREADS
 static void*   malloc_atfork(size_t sz, const void *caller);
 static void      free_atfork(void* mem, const void *caller);
-#endif
 
 /* ------------------ MMAP support ------------------  */
 
Index: b/sysdeps/generic/malloc-machine.h
===================================================================
--- a/sysdeps/generic/malloc-machine.h
+++ b/sysdeps/generic/malloc-machine.h
@@ -22,30 +22,9 @@
 
 #include <atomic.h>
 
-#ifndef mutex_init /* No threads, provide dummy macros */
+#ifndef mutex_init
 
-# define NO_THREADS
-
-/* The mutex functions used to do absolutely nothing, i.e. lock,
-   trylock and unlock would always just return 0.  However, even
-   without any concurrently active threads, a mutex can be used
-   legitimately as an `in use' flag.  To make the code that is
-   protected by a mutex async-signal safe, these macros would have to
-   be based on atomic test-and-set operations, for example. */
-typedef int mutex_t;
-
-# define mutex_init(m)          (*(m) = 0)
-# define mutex_lock(m)          ({ *(m) = 1; 0; })
-# define mutex_trylock(m)       (*(m) ? 1 : ((*(m) = 1), 0))
-# define mutex_unlock(m)        (*(m) = 0)
-# define MUTEX_INITIALIZER      (0)
-
-typedef void *tsd_key_t;
-# define tsd_key_create(key, destr) do {} while(0)
-# define tsd_setspecific(key, data) ((key) = (data))
-# define tsd_getspecific(key, vptr) (vptr = (key))
-
-# define thread_atfork(prepare, parent, child) do {} while(0)
+#error NO_THREADS no longer supported
 
 #endif /* !defined mutex_init */