Implement move semantics for iostreams

commit ca4e76f7c3a314ab068e4c89f92c6003d9d0a712
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Sep 23 11:06:23 2014 +0100

    	* config/abi/pre/gnu.ver: Adjust basic_ostream exports.
    	* include/std/istream (basic_iostream(basic_iostream&&)): Pass *this
    	to ostream constructor.
    	* include/std/ostream (basic_ostream(basic_iostream*)): Change to take
    	parameter by reference, to avoid ambiguity.
    	* testsuite/27_io/basic_ostream/cons/char/null.cc: New.

diff --git a/libstdc++-v3/config/abi/pre/gnu.ver b/libstdc++-v3/config/abi/pre/gnu.ver
index 669e36d..58c90d6 100644
--- a/libstdc++-v3/config/abi/pre/gnu.ver
+++ b/libstdc++-v3/config/abi/pre/gnu.ver
@@ -1413,9 +1413,9 @@  GLIBCXX_3.4.21 {
     _ZN9__gnu_cxx18stdio_sync_filebufI[cw]St11char_traitsI[cw]EEaSEOS3_;
     _ZN9__gnu_cxx18stdio_sync_filebufI[cw]St11char_traitsI[cw]EEC[12]EOS3_;
 
-    # basic_ostream<C,T>::basic_ostream(basic_iostream<C,T>*)
-    _ZNSoC[12]EPSd;
-    _ZNSt13basic_ostreamIwSt11char_traitsIwEEC[12]EPSt14basic_iostreamIwS1_E;
+    # basic_ostream<C,T>::basic_ostream(basic_iostream<C,T>&)
+    _ZNSoC[12]ERSd;
+    _ZNSt13basic_ostreamIwSt11char_traitsIwEEC[12]ERSt14basic_iostreamIwS1_E;
 
 } GLIBCXX_3.4.20;
 
diff --git a/libstdc++-v3/include/std/istream b/libstdc++-v3/include/std/istream
index 3a47616..d4e5d71 100644
--- a/libstdc++-v3/include/std/istream
+++ b/libstdc++-v3/include/std/istream
@@ -863,7 +863,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
       basic_iostream(const basic_iostream&) = delete;
 
       basic_iostream(basic_iostream&& __rhs)
-      : __istream_type(std::move(__rhs)), __ostream_type(this)
+      : __istream_type(std::move(__rhs)), __ostream_type(*this)
       { }
 
       // 27.7.3.3 Assign/swap
diff --git a/libstdc++-v3/include/std/ostream b/libstdc++-v3/include/std/ostream
index 748b805..619dbe4 100644
--- a/libstdc++-v3/include/std/ostream
+++ b/libstdc++-v3/include/std/ostream
@@ -386,7 +386,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
 #if __cplusplus >= 201103L
       // Non-standard constructor that does not call init()
-      basic_ostream(basic_iostream<_CharT, _Traits>*) { }
+      basic_ostream(basic_iostream<_CharT, _Traits>&) { }
 
       basic_ostream(const basic_ostream&) = delete;
 
diff --git a/libstdc++-v3/testsuite/27_io/basic_ostream/cons/char/null.cc b/libstdc++-v3/testsuite/27_io/basic_ostream/cons/char/null.cc
new file mode 100644
index 0000000..6e41c40
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_ostream/cons/char/null.cc
@@ -0,0 +1,30 @@ 
+// Copyright (C) 2014 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++11" }
+// { dg-do compile }
+
+#include <ostream>
+
+// https://gcc.gnu.org/ml/libstdc++/2014-09/msg00108.html
+struct O : std::ostream
+{
+  O() : std::ostream(NULL) { }
+  O(int) : std::ostream(nullptr) { }
+};
+
+O o;