[patch] libstdc++/67408 Handle distinct __gthread_recursive_mutex_t type.

[Jonathan Wakely]

This makes recursive_timed_mutex work for non-pthreads targets where
__gthread_mutex_t and __gthread_recursive_mutex_t are not the same
type. Thanks to Sebastian for the bug report and patch.

Tested powerpc64le-linux, committed to trunk.



commit 852d09122561d301b2980b6f9c97e88c5499006c
Author: Jonathan Wakely <jwak...@redhat.com>
Date:   Wed Sep 2 11:39:46 2015 +0100

    2015-09-02  Sebastian Huber  <sebastian.hu...@embedded-brains.de>
    
    	PR libstdc++/67408
    	* include/std/mutex (__timed_mutex_impl::_M_try_lock_until): Use
    	_Derived::_M_timedlock().
    	(timed_mutex): Add _M_timedlock() and make base class a friend.
    	(recursive_timed_mutex): Likewise.

diff --git a/libstdc++-v3/include/std/mutex b/libstdc++-v3/include/std/mutex
index deb85df..790508c 100644
--- a/libstdc++-v3/include/std/mutex
+++ b/libstdc++-v3/include/std/mutex
@@ -230,8 +230,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	    static_cast<long>(__ns.count())
 	  };
 
-	  auto __mutex = static_cast<_Derived*>(this)->native_handle();
-	  return !__gthread_mutex_timedlock(__mutex, &__ts);
+	  return static_cast<_Derived*>(this)->_M_timedlock(__ts);
 	}
 
       template<typename _Clock, typename _Duration>
@@ -293,6 +292,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     native_handle_type
     native_handle()
     { return &_M_mutex; }
+
+    private:
+      friend class __timed_mutex_impl<timed_mutex>;
+
+      bool
+      _M_timedlock(const __gthread_time_t& __ts)
+      { return !__gthread_mutex_timedlock(&_M_mutex, &__ts); }
   };
 
   /// recursive_timed_mutex
@@ -346,6 +352,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     native_handle_type
     native_handle()
     { return &_M_mutex; }
+
+    private:
+      friend class __timed_mutex_impl<recursive_timed_mutex>;
+
+      bool
+      _M_timedlock(const __gthread_time_t& __ts)
+      { return !__gthread_recursive_mutex_timedlock(&_M_mutex, &__ts); }
   };
 #endif
 #endif // _GLIBCXX_HAS_GTHREADS