Revert "Revert "Pull the pthread_key_t functions out of pthread.c.""

This reverts commit 6260553d48f6fd87ca220270bea8bafdde5726ec

(Removing the accidental libm/Android.mk change.)

Change-Id: I6cddd9857c31facc05636e8221505b3d2344cb75
diff --git a/libc/bionic/pthread_internal.h b/libc/bionic/pthread_internal.h
index bc68291..24b420c 100644
--- a/libc/bionic/pthread_internal.h
+++ b/libc/bionic/pthread_internal.h
@@ -60,6 +60,11 @@
 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 )