gdb/

gdb/
	Replace public function varobj_list by all_root_varobjs iterator.
	* mi/mi-cmd-var.c (struct mi_cmd_var_update, mi_cmd_var_update_iter):
	New.
	(mi_cmd_var_update): Replace the varobj_list call by all_root_varobjs.
	Remove the variables rootlist, cr.  New variable data.
	* varobj.c (rootcount, varobj_list): Remove.
	(install_variable, uninstall_variable): Remove the rootcount updates.
	(all_root_varobjs): New function.
	(varobj_invalidate): Use the all_root_varobjs call.  Move the code to...
	(varobj_invalidate_iter): ... a new function.
	* varobj.h (varobj_list): Remove the prototype.
	(all_root_varobjs): New prototype.