Teach target_* commands to set INTERFACE properties of IMPORTED targets

Now, several `INTERFACE_*` properties can be set on `IMPORTED` targets,
not only via `set_property` and `set_target_properties` but also via
`target_compile_definitions`, `target_compile_features`,
`target_compile_options`, `target_include_directories`, `target_sources`
and `target_link_libraries`.

Fixes: #15689
Issue: #17197

1 files changed, 2 insertions, 12 deletions

diff --git a/Source/cmTargetIncludeDirectoriesCommand.cxx b/Source/cmTargetIncludeDirectoriesCommand.cxx
index 4646c7e..dcec830 100644
--- a/Source/cmTargetIncludeDirectoriesCommand.cxx
+++ b/Source/cmTargetIncludeDirectoriesCommand.cxx
@@ -21,22 +21,12 @@ bool cmTargetIncludeDirectoriesCommand::InitialPass(
                                ArgumentFlags(PROCESS_BEFORE | PROCESS_SYSTEM));
 }
 
-void cmTargetIncludeDirectoriesCommand::HandleImportedTarget(
-  const std::string& tgt)
-{
-  std::ostringstream e;
-  e << "Cannot specify include directories for imported target \"" << tgt
-    << "\".";
-  this->Makefile->IssueMessage(cmake::FATAL_ERROR, e.str());
-}
-
 void cmTargetIncludeDirectoriesCommand::HandleMissingTarget(
   const std::string& name)
 {
   std::ostringstream e;
   e << "Cannot specify include directories for target \"" << name
-    << "\" "
-       "which is not built by this project.";
+    << "\" which is not built by this project.";
   this->Makefile->IssueMessage(cmake::FATAL_ERROR, e.str());
 }
 
@@ -79,7 +69,7 @@ bool cmTargetIncludeDirectoriesCommand::HandleDirectContent(
     }
     tgt->AddSystemIncludeDirectories(sdirs);
   }
-  return true;
+  return true; // Successfully handled.
 }
 
 void cmTargetIncludeDirectoriesCommand::HandleInterfaceContent(