We still want security_inherit_p to default to 't', otherwise bcms::folder::create_folder breaks, because null is not a valid boolean value. This is also consistent with what the comments in the function says (default true)
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 ...