std::auto_ptr deprecation warning in libstdc++ 5.1

[Andrew Potter <agpotter gmail com>]

Hi everybody,

As you probably know, std::auto_ptr got deprecated in the C++11
standard and is scheduled for removal in C++17. After upgrading to
Fedora 22, I see that g++ is now issuing a warning when it sees use of
std::auto_ptr. Unfortunately there is one in glibmm's objectbase.h:

In file included from /usr/include/glibmm-2.4/glibmm/object.h:29:0,
                 from /usr/include/giomm-2.4/giomm/simpleaction.h:27,
                 from application.cpp:19:
/usr/include/glibmm-2.4/glibmm/objectbase.h:215:13: warning:
‘template<class> class std::auto_ptr’ is deprecated
[-Wdeprecated-declarations]
 static std::auto_ptr<Threads::Mutex> extra_object_base_data_mutex;
             ^
In file included from /usr/include/c++/5.1.1/memory:81:0,
                 from /usr/include/glibmm-2.4/glibmm/objectbase.h:32,
                 from /usr/include/glibmm-2.4/glibmm/object.h:29,
                 from /usr/include/giomm-2.4/giomm/simpleaction.h:27,
                 from application.cpp:19:
/usr/include/c++/5.1.1/bits/unique_ptr.h:49:28: note: declared here
   template<typename> class auto_ptr;
                            ^

I don't think this is fully resolvable until the next ABI/API break
(which maybe we should think about in the 2017 timeframe?), but in the
meantime, does anyone have a clever idea to hide this particular
warning without disabling -Wdepreciated-declarations altogether? Or
maybe we can make some ABI-compatible Glib::auto_ptr ?