pg_service.conf file with iso-8859-1 parameters

This seems user-unfriendly, both in the error message (because it really isn't a syntax error) and in the behaviour itself (because it doesn't work when sometimes it should).

For example, if I have a service file with gssencmode=disable set, that service file cannot be used by a psql client linked against libpq from version 10. Even if the behavior would be identical (since v10 doesn't have gssencmode).

Is there a particular reason we (1) refuse unknown parameters in the file, and (2) call it a "syntax error"?

The documentation just says it's "INI format" file -- though in my experience most other INI file parsers just ignore extra parameters included..

//Magnus