[exim] exim4: headers check syntax?

Hi,

in exim3, there was an option to check the syntax of mail headers
(headers_check_syntax or so).

How do I enable that with exim4?


Cyrus complains about invalid headers, so I want to check them before
such mail is handed over to cyrus. Messages with invalid headers should
be rejected before accepting them for not to have a possible exploit for
SPAMers.


GH