gdb/

	* varobj.h (varobj_languages): Add vlang_ada definition to the list
	of supported languages.
	* varobj.c: Add top definitions and basic implementation of the
	following callbacks: ada_number_of_children, ada_name_of_variable,
	ada_name_of_child, ada_path_expr_of_child, ada_value_of_root,
	ada_value_of_child, ada_type_of_child, ada_value_of_variable.
	(languages): Register Ada-specific callbacks.
	(variable_language): Add the Ada case in the language setter switch.