PR libstdc++/82481 Suppress clang-tidy warnings

	PR libstdc++/82481
	* include/std/mutex (call_once): Suppress clang-tidy warnings about
	dangling references.

From-SVN: r253724

libstdc++-v3/ChangeLog

+2017-10-13  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/82481
+	* include/std/mutex (call_once): Suppress clang-tidy warnings about
+	dangling references.
+
 2017-10-10  Jonathan Wakely  <jwakely@redhat.com>
 
 	* include/bits/streambuf_iterator.h (istreambuf_iterator::equal):

libstdc++-v3/include/std/mutex

@@ -688,6 +688,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
         __set_once_functor_lock_ptr(0);
 #endif
 
+#ifdef __clang_analyzer__
+      // PR libstdc++/82481
+      __once_callable = nullptr;
+      __once_call = nullptr;
+#endif
+
       if (__e)
 	__throw_system_error(__e);
     }