In commit f3ad061858 (Add usage requirements to update direct link
dependencies, 2022-01-12, v3.23.0-rc1~44^2), we evaluated the transitive
closure of `INTERFACE_LINK_LIBRARIES` as a non-linking usage requirement.
That left out `INTERFACE_LINK_LIBRARIES_DIRECT` link dependencies that
appear behind private dependencies of a static library, guarded by the
`$<LINK_ONLY:...>` generator expression. At the time, that decision was
intentional, in order to prevent arbitrary usage requirements from
leaking out of `PRIVATE` dependencies.
Since then, we've revised evaluation of `LINK_LIBRARIES` to distinguish
between collecting link dependencies and other usage requirements. Use
that information when following `INTERFACE_LINK_LIBRARIES` to collect
the matching kind of requirements from `INTERFACE_LINK_LIBRARIES_DIRECT`.
Fixes: #22496
Link line construction starts with `LINK_LIBRARIES` and appends
dependencies from the transitive closure of `INTERFACE_LINK_LIBRARIES`.
Only the entries of `LINK_LIBRARIES` are considered direct link
dependencies. In some advanced use cases, particularly involving static
libraries and static plugins, usage requirements need to update the list
of direct link dependencies. This may mean adding new items, removing
existing items, or both.
Add target properties to encode these usage requirements:
* INTERFACE_LINK_LIBRARIES_DIRECT
* INTERFACE_LINK_LIBRARIES_DIRECT_EXCLUDE
Fixes: #22496
