[libstdc++] Build system cleanup [3/n]

[Benjamin Kosnik]

> 2005-04-04  Kelley Cook  <kcook@gcc.gnu.org>
> 
> 	* linkage.m4 (GLIBCXX_CHECK_BUILTIN_MATH_DEC): Use m4 translit macro 
> 	to convert to uppercase instead of shelling out to tr.
> 	* acconfig.h: Remove now redundant HAVE__BUILTINS_*.
> 	* configure, config.h.in: Regenerate.

OK

-benjamin