v3: Move AC_PROG_CC/CXX code block into configure.ac.

[Benjamin Kosnik]

> 2009-07-30  Ralf Wildenhues  <Ralf.Wildenhues@gmx.de>
> 
> 	* configure.ac: Move guarded checks for CC and CXX ...
> 	* acinclude.m4 (GLIBCXX_CONFIGURE): ... from here.
> 	* configure: Regenerate.

OK.

-benjamin