PG 7.3 doesn't support 'current_timestamp' as a literal any more (it still is defined as a variable, of course). Also define_function_args assumes NULL as the default value if none is specified, 'null' <> NULL ...
Added define_function_arg calls to non-content-revision objects and to create_type and create_attributes, so we can do these operations via Tcl. Content revisions, due to LOB/non-LOB issues and the incompatibility of LOB operations between DBs need their own "smart" Tcl API.