Remove 'noreturn' attribute from friend declaration. This attribute will be
inherited from the previous out-of-class declaration, and attributes on friend
function declarations are ill-formed in C++11.

llvm-svn: 168853
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: e1f363c7249c912c140ba86ce7f8f72e5c9ece8d
diff --git a/include/exception b/include/exception
index 5b75fb0..51a48c8 100644
--- a/include/exception
+++ b/include/exception
@@ -143,7 +143,7 @@
         {return !(__x == __y);}
 
     friend exception_ptr current_exception() _NOEXCEPT;
-    _LIBCPP_NORETURN friend void rethrow_exception(exception_ptr);
+    friend void rethrow_exception(exception_ptr);
 };
 
 template<class _Ep>