* src/cms.h (struct ksba_cms_s): Add flag 'auth_mode'.
* src/cms.c (ksba_cms_set_content_type): Set flag.
(ksba_cms_set_message_digest): Extend to be used for setting the
authtag.
(ct_build_enveloped_data): Add new state WAITTAG and write the
authtag.