Explicitly disallow default c-tor

Change-Id: Ia52995a459443159e80383d5b396c3edd90a08ae
diff --git a/libc/private/ScopedPthreadMutexLocker.h b/libc/private/ScopedPthreadMutexLocker.h
index 43dbdc1..58462e3 100644
--- a/libc/private/ScopedPthreadMutexLocker.h
+++ b/libc/private/ScopedPthreadMutexLocker.h
@@ -34,7 +34,7 @@
  private:
   pthread_mutex_t* mu_;
 
-  DISALLOW_COPY_AND_ASSIGN(ScopedPthreadMutexLocker);
+  DISALLOW_IMPLICIT_CONSTRUCTORS(ScopedPthreadMutexLocker);
 };
 
 #endif // SCOPED_PTHREAD_MUTEX_LOCKER_H