long double and GLIBCPP_CHECK_MATH_SUPPORT

[Benjamin Kosnik]

> Ben> Please send a patch with a ChangeLog entry for config/os/aix/*. I'm eager 
> Ben> to get this in.
> 
> 	Already sent.  The other pieces still needed are the libio.h __P
> macros patch, mknumeric_limits patch, and configure strtold() declaration
> check.

Ok. Do you want to post this as a unified patch, or wait till Phil's 
stuff gets in?

THe configure and mknumeric bits seem separate, so perhaps you could post 
them, with a complete ChangeLog entry please.

-benjamin