* fold-const.c (all_ones_mask_p, sign_bit_p, simple_operand_p,
	fold_real_zero_addition_p, reorder_operands_p,
	div_if_zero_remainder, fold_undefer_overflow_warnings,
	int_binop_types_match_p, fold_convert_const_int_from_int,
	fold_convert_const_int_from_real,
	fold_convert_const_int_from_fixed,
	fold_convert_const_real_from_real,
	fold_convert_const_real_from_fixed,
	fold_convert_const_fixed_from_fixed,
	fold_convert_const_fixed_from_int,
	fold_convert_const_fixed_from_real, maybe_lvalue_p,
	fold_checksum_tree, fold_check_failed, print_fold_checksum,
	debug_fold_checksum, multiple_of_p): Constify.
	* tree-flow-inline.h (get_lineno): Likewise.
	* tree-flow.h (get_lineno): Likewise.
	* tree-object-size.c (compute_object_offset, addr_object_size,
	alloc_object_size, pass_through_call): Likewise.
	* tree-pretty-print.c (op_symbol, print_call_name,
	print_struct_decl, do_niy): Likewise.
	* tree.h (fold_undefer_overflow_warnings, multiple_of_p,
	debug_fold_checksum): Likewise.

From-SVN: r128120