tuned signature (again, amending f32ac01aef5e), e.g. relevant for Isabelle/DOF;
(*** Isabelle/Pure bootstrap: initial setup ***)
ML_file "ML/ml_statistics.ML";
ML_file "General/exn.ML";
ML_file "General/output_primitives.ML";
ML_file "Concurrent/thread_attributes.ML";
ML_file "Concurrent/thread_data.ML";
ML_file "Concurrent/thread_position.ML";
ML_file "ML/ml_recursive.ML";