target_link_libraries: Allow use with targets in other directories

Previously the command did not allow naming targets on the LHS that
were not created in the calling directory.  Lift this restriction to
enable more flexible use by projects.

Fixes: #17943

1 files changed, 9 insertions, 2 deletions

diff --git a/Source/cmTargetLinkLibrariesCommand.cxx b/Source/cmTargetLinkLibrariesCommand.cxx
index 699fff8..53f1213 100644
--- a/Source/cmTargetLinkLibrariesCommand.cxx
+++ b/Source/cmTargetLinkLibrariesCommand.cxx
@@ -364,7 +364,7 @@ bool cmTargetLinkLibrariesCommand::HandleLibrary(const std::string& lib,
   if (this->CurrentProcessingState != ProcessingKeywordLinkInterface &&
       this->CurrentProcessingState != ProcessingPlainLinkInterface) {
 
-    // Assure that the target on the LHS was created in the current directory.
+    // Find target on the LHS locally
     cmTarget* t =
       this->Makefile->FindLocalNonAliasTarget(this->Target->GetName());
     if (!t) {
@@ -377,11 +377,18 @@ bool cmTargetLinkLibrariesCommand::HandleLibrary(const std::string& lib,
         }
       }
     }
+
+    // If no local target has been found, find it in the global scope
+    if (!t) {
+      t = this->Makefile->GetGlobalGenerator()->FindTarget(
+        this->Target->GetName(), true);
+    }
+
     if (!t) {
       std::ostringstream e;
       e << "Attempt to add link library \"" << lib << "\" to target \""
         << this->Target->GetName()
-        << "\" which is not built in this directory.";
+        << "\" which does not exist or is an alias target.";
       this->Makefile->IssueMessage(cmake::FATAL_ERROR, e.str());
       return false;
     }