PR middle-end/21024

	* builtins.c (expand_builtin_strcat): Convert the result of
	strlen to the right type.
	* fold-const.c (fold_binary) <PLUS_EXPR>: Use fold_convert to
	avoid creating type mismatches.
	<GE_EXPR>: Pass op0 and op1 to fold_build2 to avoid creating
	type mismatches.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@98244 138bc75d-0d04-0410-961f-82ee72b054a4