Tighten up vfprintf width, precision, and total length overflow handling.

Tighten up vfprintf width, precision, and total length overflow handling.

	With help from Paul Eggert, Carlos O'Donell, and Roland McGrath.
	* stdio-common/printf-parse.h (read_int): Change return type to
	'int', return -1 on INT_MAX overflow.
	* stdio-common/vfprintf.c (vfprintf): Validate width and precision
	against overflow of INT_MAX.  Set errno to EOVERFLOW when 'done'
	overflows INT_MAX.  Check for overflow of in-format-string precision
	values properly.  Use EOVERFLOW rather than ERANGE throughout.  Use
	SIZE_MAX not INT_MAX for integer overflow test.
	* stdio-common/printf-parsemb.c: If read_int signals an overflow,
	skip the construct in the format string but do not record anything.
	* stdio-common/bug22.c: Adjust to test both width/prevision
	INT_MAX overflow as well as total length INT_MAX overflow.  Check
	explicitly for proper errno values.