Index: glibc-2.21/sysdeps/mach/bits/libc-lock.h
===================================================================
--- glibc-2.21.orig/sysdeps/mach/bits/libc-lock.h
+++ glibc-2.21/sysdeps/mach/bits/libc-lock.h
@@ -124,8 +124,15 @@ struct __libc_once
 #define __libc_mutex_unlock __mutex_unlock
 #endif
 
-#define __libc_key_create(KEY,DEST) cthread_keycreate (KEY)
-#define __libc_setspecific(KEY,VAL) cthread_setspecific (KEY, VAL)
+#define __libc_ctf_call(FUNC, ARGS, ELSE) \
+  (&_cthread_init_routine && _cthread_init_routine \
+    ? FUNC ARGS : ELSE)
+
+extern void *(*_cthread_init_routine) (void) __attribute__ ((weak));
+#define __libc_key_create(KEY,DEST) \
+  __libc_ctf_call (cthread_keycreate, (KEY), 1)
+#define __libc_setspecific(KEY,VAL) \
+  __libc_ctf_call (cthread_setspecific, (KEY, VAL), 0)
 void *__libc_getspecific (__libc_key_t key);
 
 /* XXX until cthreads supports recursive locks */
Index: glibc-2.21/sysdeps/mach/hurd/bits/libc-lock.h
===================================================================
--- glibc-2.21.orig/sysdeps/mach/hurd/bits/libc-lock.h
+++ glibc-2.21/sysdeps/mach/hurd/bits/libc-lock.h
@@ -200,8 +200,15 @@ struct __libc_once
 /* Type for key of thread specific data.  */
 typedef cthread_key_t __libc_key_t;
 
-#define __libc_key_create(KEY,DEST) cthread_keycreate (KEY)
-#define __libc_setspecific(KEY,VAL) cthread_setspecific (KEY, VAL)
+#define __libc_ctf_call(FUNC, ARGS, ELSE) \
+  (&_cthread_init_routine && _cthread_init_routine \
+    ? FUNC ARGS : ELSE)
+
+extern void *(*_cthread_init_routine) (void) __attribute__ ((weak));
+#define __libc_key_create(KEY,DEST) \
+  __libc_ctf_call (cthread_keycreate, (KEY), 1)
+#define __libc_setspecific(KEY,VAL) \
+  __libc_ctf_call (cthread_setspecific, (KEY, VAL), 0)
 void *__libc_getspecific (__libc_key_t key);
 
 #endif /* _CTHREADS_ */
Index: glibc-2.21/sysdeps/mach/hurd/cthreads.c
===================================================================
--- glibc-2.21.orig/sysdeps/mach/hurd/cthreads.c
+++ glibc-2.21/sysdeps/mach/hurd/cthreads.c
@@ -55,14 +55,11 @@ cthread_setspecific (key, val)
   return -1;
 }
 
-/* Call cthread_getspecific which gets a pointer to the return value instead
-   of just returning it.  */
+/* Follow NPTL, return NULL when pthread is not available. */
 void *
 weak_function
 __libc_getspecific (key)
      cthread_key_t key;
 {
-  void *val;
-  cthread_getspecific (key, &val);
-  return val;
+  return NULL;
 }