LINK_LIBRARIES: Evaluate separately for linking and usage requirements

We evaluate `LINK_LIBRARIES` and `INTERFACE_LINK_LIBRARIES` for two purposes:

* Constructing the link line.
* Collecting usage requirements.

We evaluate `INTERFACE_LINK_LIBRARIES` separately for each purpose in
order to support the `$<LINK_ONLY:...>` generator expression used to
express private link dependencies of a static library.  Previously we
only evaluated `LINK_LIBRARIES` for linking, and used that result for
collecting usage requirements too.  Therefore `$<LINK_ONLY:...>` does
not work in `LINK_LIBRARIES`.

With the introduction of `INTERFACE_LINK_LIBRARIES_DIRECT`, evaluation
of `LINK_LIBRARIES` now needs to distinguish these two cases in order to
honor link dependencies encountered through `$<LINK_ONLY:...>` without
also exposing other usage requirements through private dependencies of a
static library.  Revise internal infrastructure to distinguish the two
cases when evaluating `LINK_LIBRARIES`.  Make the information available
in code paths for `INTERFACE_LINK_LIBRARIES_DIRECT` and `LINK_ONLY`.
Defer actually using the information to later commits.

Issue: #22496

1 files changed, 4 insertions, 2 deletions

diff --git a/Source/cmQtAutoGenInitializer.cxx b/Source/cmQtAutoGenInitializer.cxx
index a01e6aef68..a47b3c03a7 100644
--- a/Source/cmQtAutoGenInitializer.cxx
+++ b/Source/cmQtAutoGenInitializer.cxx
@@ -114,7 +114,8 @@ bool StaticLibraryCycle(cmGeneratorTarget const* targetOrigin,
       }
       // Collect all static_library dependencies from the test target
       cmLinkImplementationLibraries const* libs =
-        testTarget->GetLinkImplementationLibraries(config);
+        testTarget->GetLinkImplementationLibraries(
+          config, cmGeneratorTarget::LinkInterfaceFor::Link);
       if (libs) {
         for (cmLinkItem const& item : libs->Libraries) {
           cmGeneratorTarget const* depTarget = item.Target;
@@ -1266,7 +1267,8 @@ bool cmQtAutoGenInitializer::InitAutogenTarget()
       std::map<cmGeneratorTarget const*, std::size_t> commonTargets;
       for (std::string const& config : this->ConfigsList) {
         cmLinkImplementationLibraries const* libs =
-          this->GenTarget->GetLinkImplementationLibraries(config);
+          this->GenTarget->GetLinkImplementationLibraries(
+            config, cmGeneratorTarget::LinkInterfaceFor::Link);
         if (libs) {
           for (cmLinkItem const& item : libs->Libraries) {
             cmGeneratorTarget const* libTarget = item.Target;