Add entire link interface transitive closure as target depends.

This was missing from commit 30962029 (Make targets depend on the
link interface of their dependees., 2012-12-26), which caused
only immeditate entries of the link interface to become target
depends.

Source/cmComputeTargetDepends.cxx

@@ -282,6 +282,8 @@ void cmComputeTargetDepends::AddInterfaceDepends(int depender_index,
       if(emitted.insert(*lib).second)
         {
         this->AddTargetDepend(depender_index, lib->c_str(), true);
+        this->AddInterfaceDepends(depender_index, lib->c_str(),
+                                  true, emitted);
         }
       }
     }