* lib/Automake/Variable.pm (check_defined_unconditionally): Add

* lib/Automake/Variable.pm (check_defined_unconditionally): Add
the $parent_cond argument.
(output): Use $self->name in diagnostic not $self.
(variable_value_as_list): Rename as ...
(value_as_list): ... this.  Declare as a method.  Take a $parent_cond
argument and pass it to check_defined_unconditionally.  Do not call
variable_assert, now that this is a method.
(variable_assert): Delete (unused).
* automake.in (traverse_variable_recursively_worker): Adjust to
use check_defined_unconditionally and value_as_list as a methods.