* acinclude.m4: Add C++ linkage check for strtof.
	* aclocal.m4: Rebuilt.
	* config.h.in: Rebuilt.
	* configure: Rebuilt.
	* config/locale/c_locale_generic.cc: Conditionally include
	<ieeefp.h>.  Improve handling and error checking of float
	and long double input for non-C99 configurations.

From-SVN: r49546