* asprintf.c: Don't define USE_STDARG.  Use VPARAMS, VA_OPEN,
	VA_FIXEDARG & VA_CLOSE.

	* vasprintf.c: Check HAVE_STRING_H when including string.h.
	(checkit): Delete redundant prototype.  Add ATTRIBUTE_PRINTF_1.
	Use VA_OPEN, VA_FIXEDARG & VA_CLOSE.  Free allocated string.

From-SVN: r45382