[v3] locale cache PR 7076,8761

[B. Kosnik]

>abi-check also believes that std::locale::_Impl::_S_static_caches is
>incompatible.

Yo dude you have to explicitly version new symbols like _S_static_caches.

I changed the rules because apparently this was unclear. Unless you do
the intaglio in linker-map.gnu, new symbols get added under the old
version name. 

Now all new symbols are incompatible unless newly-versioned. I suspect
this is the problem: if it is, you'll just have to fix linker-map.gnu.

><lightbulb> The previous version doesn't pass abi-check because
>facet_vec is too large.  If I left it alone, but created a second
>array facet_vec2 and used that instead, then the old array symbol will
>still be there and the same size, but we won't use it anymore.  That
>should satisfy abi-check.
></lightbulb>
>
>What do you think?

This sound promising, and much like what has been done in the past. See
the GXX_ABI bits in global.cc and locale.cc.

-benjamin