new warnings from basic_string

[Paolo Carlini]

Lars Gullik Bjønnes wrote:

>Seems that _GLIBCXX_DEBUG is now required to trigger it.
>
>#define _GLIBCXX_DEBUG 1
>
>#include <map>
>
>void foo()
>{
>        typedef std::map<int, int> MangledMap;
>        MangledMap mangledNames;
>        MangledMap::const_iterator it = mangledNames.find(0);
>}
>  
>
Yes, I can reproduce this: can you please file a complete Bugzilla PR? 
And add in CC, Ian Lance Taylor (ian@airs.com)

Thanks!
Paolo.