overwork type of function call and handle usage of identifiers from C_env and not from current translation unit

make intermediate step with abstract over, to ensure binding of free variabel "tmpvar". Also fix error where temp vars for array assignments would have the wrong value

rough port of Isabelle_C_Clean (aka 'wrapper') to Isa24. Abandon of Frederics code related to his MetaModel.

Merge with Isabelle_C(24) AFP and Isabelle_C(2021-1) local; Port and rough testing. Problems with some outputs, Tuongs C11To99 excluded.