* configure.in: Check whether printf family supports printing

	* configure.in: Check whether printf family supports printing
	long doubles or not and define PRINTF_HAS_LONG_DOUBLE if so.
	* acconfig.h: Provide default undef for PRINTF_HAS_LONG_DOUBLE.
	* configure: Regenerate.
	* valprint.c (print_floating): Use PRINTF_HAS_LONG_DOUBLE.
	* c-exp.y (parse_number): Use PRINTF_HAS_LONG_DOUBLE.
	* configure.in: Fix have_gregset and have_fpregset autoconf
	variable names so that they match the pattern required to
	cache them.