INTERFACE_LIBRARY: Avoid codepaths which set unneeded properties.

As an INTERFACE_LIBRARY has no direct link dependencies, we can
short-circuit in cmGeneratorExpressionEvaluator and
in cmGlobalGenerator::CheckLocalGenerators.

As they do not generate any output directly, any generate- or install-
related code acn also be short-circuited. Many of the local generators
already do this.

Because only INTERFACE related properties make sense on INTERFACE_LIBRARY
targets, avoid setting other properties, for example via defaults.

1 files changed, 8 insertions, 0 deletions

diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index 989aa5f..30a1557 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -868,6 +868,10 @@ void cmMakefile::ConfigureFinalPass()
   for (cmTargets::iterator l = this->Targets.begin();
        l != this->Targets.end(); l++)
     {
+    if (l->second.GetType() == cmTarget::INTERFACE_LIBRARY)
+      {
+      continue;
+      }
     l->second.FinishConfigure();
     }
 }
@@ -2256,6 +2260,10 @@ void cmMakefile::ExpandVariablesCMP0019()
        l != this->Targets.end(); ++l)
     {
     cmTarget &t = l->second;
+    if (t.GetType() == cmTarget::INTERFACE_LIBRARY)
+      {
+      continue;
+      }
     includeDirs = t.GetProperty("INCLUDE_DIRECTORIES");
     if(mightExpandVariablesCMP0019(includeDirs))
       {