TR1 Math Special Functions

[Paolo Carlini]

Hi Ed,

> So, would it be better for me to put these __builtin_isnan (actually 
> behind a function that wraps this) Or we could find all the functions 
> wrapped in the C99_MATH guards for which we have such intrinsics and 
> provide alternate implementations.
>
> I think I'll start the former with a comment to replace it with just 
> the std::isnan if/when we do the second option.

you are right in raising this issue, I had the same thought. I agree 
with you, better decouple the issues and first commit a "minimal" patch 
adding the new TR1 facilities. Then we can re-examine those builtins and 
figure out which ones are completely expanded and can directly implement 
the standard mandated classification macros in a very simple way.

Paolo.