Linking does have one thing that it implies: it's maybe a bit "closer"
relationship between the parts than "mkisofs" implies. So there is
definitely a higher _correlation_ between "derived work" and "linking",
but it's really a correlation, not a causal relationship.
But it wasn't the "act of linking" that caused
that to happen, but simply the fact that they were part of a bigger whole,
and were meaningless apart from each other.
Think of this in the sense of a book. Does binding pages together create a
"derived work"? Not always: you can have anthologies (which are
*aggregations* of works with *independent* copyright), and the binding of
pages together didn't really do anything to the independent pieces. But
clearly, if you're talking about individual pages in one story, then each
individual page is not an independent work in itself.