PR mi/10586
* varobj.c (ANONYMOUS_STRUCT_NAME): Define.
(ANONYMOUS_UNION_NAME): Define.
(is_path_expr_parent): New function.
(get_path_expr_parent): New function.
(is_anonymous_child): New function.
(create_child_with_value): If the child is anonymous and without
a name, assign an object name to it.
(c_describe_child): Use get_path_expr_parent to determine
the parent expression.
If there field represents an anonymous struct or union and
has no name, set an appropriate display name and expression.
(cplus_describe_child): Likewise.