Notifies the DATATRIEVE interpreter that the DECforms forms to
       be used are linked with the application rather than being stored
       in external files (default case) and provides an address to get them.
       Alternatively, it can reset the default case.
       It is relevant only for applications calling the DATATRIEVE API.

       Syntax:

       FN$SET_FORM_TABLE_ADDR (form_table_addr, enable_flag).