* ada-exp.y (write_object_renaming, write_var_or_type)

	* ada-exp.y (write_object_renaming, write_var_or_type)
	(write_ambiguous_var, write_var_from_sym): Make blocks const.
	* ada-lang.c (replace_operator_with_call)
	(find_old_style_renaming_symbol): Make blocks const.
	* ada-lang.h (ada_find_renaming_symbol): Update.
	(struct ada_symbol_info) <block>: Now const.
	* breakpoint.c (watch_command_1): Update.
	* breakpoint.h (struct watchpoint) <exp_valid_block,
	cond_exp_valid_block>: Now const.
	* c-exp.y (classify_inner_name, classify_name): Make block
	argument const.
	* expprint.c (print_subexp_standard) <OP_VAR_VALUE>: Make 'b'
	const.
	* expression.h (innermost_block, parse_exp_1): Update.
	(union exp_element) <block>: Now const.
	* gdbtypes.c (lookup_template_type, lookup_enum, lookup_union)
	(lookup_struct): Make block argument const.
	* gdbtypes.h (lookup_template_type): Update.
	* go-exp.y (classify_name, classify_packaged_name)
	(package_name_p): Make block argument const.
	* objc-lang.c (lookup_struct_typedef): Make block argument const.
	* objc-lang.h (lookup_struct_typedef): Update.
	* parse.c (parse_exp_in_context, parse_exp_1)
	(write_exp_elt_block): Make block arguments const.
	(expression_context_block, innermost_block): Now const.
	* parser-defs.h (write_exp_elt_block): Update.
	(expression_context_block, innermost_block, block_found): Now
	const.
	* printcmd.c (struct display) <block>: Now const.
	* symtab.h (lookup_struct, lookup_union, lookup_enum): Update.
	* valops.c (address_of_variable): Make block argument const.
	* value.h (value_of_variable): Update.
	* varobj.c (struct varobj_root) <valid_block>: Now const.