Exclude the LINK_LIBRARIES related properties from INTERFACE evaluation.

These interface-related link-libraries properties are used to determine
the value of the other INTERFACE properties, so we were getting infinite
recursion and segfaults otherwise.

Tests/CompatibleInterface/iface2.cpp

@@ -0,0 +1,7 @@
+
+#include "iface2.h"
+
+int Iface2::foo()
+{
+  return 0;
+}