Use of C99 extra long double math functions after r236148

Yesterday r236148 (Allow inclusion of libc++ <cmath> to work after 
including math.h) was comitted to head, many thanks.

Does this mean, that extra long double functions like acoshl, expm1l or 
log1pl are now "really implemented"? As far as I understand, they had 
only been declared before?

If this is right, are they usable on a recent CURRENT, built with gcc42 
(system compiler), by ports which use gcc46 (not clang)? If not, are 
there any plans to implement these functions in the near future?

The use of C99 extra long double functions would be of interest for 
example for programs like math/R, especially its upcoming releases.

Many thanks for any clarification.

Regards,
Rainer Hurling