Forte compiler doesn't support empty struct define or declare.
    
    The list of refering files:
                    ~/evolution/camel/camel-mime-filter-from.c
                    ~/evolution/camel/camel-vee-store.c
                    ~/evolution/camel/providers/local/camel-mbox-summary.c
                    ~/evolution/camel/providers/local/camel-spool-summary.c 

    In these files there are some zero struct declaration that Forte
doesn't accept.

How often does this happen? 

Always.

Additional Information:

We should change the declaration of such zero struct.
Please give a discuss and we will add a patch soon.