[v3] speedup numpunct cache a bit

[Jerry Quinn]

Nathan Myers writes:
 > On Fri, Jun 27, 2003 at 10:38:02PM -0400, Jerry Quinn wrote:
 > > This moves the code for __use_cache<numpunct> to locale_facets.tcc.
 > 
 > Making it inline is a wondrous thing, but all inlines must go in 
 > ".h" files.  Everything in a .tcc file is supposed to be able to 
 > be declared "export" and not need to be seen at instantiation time, 
 > meaning (mainly) no public class declarations and no inlines.

<novice> How does export work? </novice>

__use_cache is only being used within the .tcc file.  Does it still
have to be in the .h?  Why doesn't this apply to std::use_facet and
std::has_facet - or should it?

 > This might not have been explained anywhere that you would have 
 > been likely to encounter.

No problem.  Is there a place in the docs or guidelines that this
tidbit should go?

Jerry