[v3] Fix PR libstdc++/10276

[Benjamin Kosnik]

>OK, the reason we're getting memory leaks is that the locale cache was never
>getting deleted.  The callback got registered within the first call to
>basic_ios::init, but the callback list was blown away by the second call,
>hence no deletion.

Thanks for looking at this.

>This doesn't address the zero allocation issues so we still leak the bytes for
>the standard stream caches.

Yes. I'm currently knee-deep in dejagnu surgery and can't look at this
at the moment. I'm anticipating a fix for 3.3/3.4 in a bit.

>2003-04-03  Jerry Quinn  <jlquinn@optonline.net>
>
>        * src/ios.cc (ios_base::_M_init): Remove _M_callbacks initialization.

please put this in 3.3, and 3.4. 

thanks!

-benjamin