ctype optimization work

[Paolo Carlini]

Jerry Quinn wrote:

>Any thoughts?
>  
>
Well, mine is *really* down-to-earth: as my preliminary tests show

    http://gcc.gnu.org/ml/libstdc++/2003-11/msg00351.html

dealing with the wchar_t case first with a trivial table prepared at 
construction time, doesn't remove the virtual call overhead and doesn't 
provide all the advantages of a dynamic cache, but for sure promise to 
speed up noticeably many applications, in particular when the 
time_get/time_put facets are involved:

    http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13341

I mean to just implement this baseline thing, against which we can judge 
more sophisticated, but tricky alternatives.

Paolo.