[PATCH] libstdc++: Fix the test for rvalue stream extraction

[Ville Voutilainen via Gcc-patches]

    libstdc++-v3/ChangeLog:

            * testsuite/27_io/rvalue_streams.cc: Run the extraction to a char*
            for C++17 and lower only.

diff --git a/libstdc++-v3/testsuite/27_io/rvalue_streams.cc b/libstdc++-v3/testsuite/27_io/rvalue_streams.cc
index ad4d11c7cf3..487aa4deedd 100644
--- a/libstdc++-v3/testsuite/27_io/rvalue_streams.cc
+++ b/libstdc++-v3/testsuite/27_io/rvalue_streams.cc
@@ -53,7 +53,9 @@ test02()
   VERIFY( x.as_rvalue == true );
 
   char arr[2];
+#if __cplusplus <= 201703L
   std::istringstream("x") >> &arr[0];
+#endif
   std::istringstream("x") >> arr;
 }