added read_const_exprs (from Pure/Isar/code_unit.ML);
added read_const_exprs (from Pure/Isar/code_unit.ML);

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle