* tree.h (enum size_type_kind): Remove USIZETYPE, UBITSIZETYPE.
	(usize_type, ubitsizetype): Remove.
	* stor-layout.c (set_sizetype): Don't initialize usizetype,
	ubitsizetype.
	* fold-const.c (size_diffop): TYPE can never be ubitsizetype.

From-SVN: r86422