extern int dkim_key_length; /* Expansion variable, length of signing key in bits */
extern void *dkim_signatures; /* Actually a (pdkim_signature *) but most files do not need to know */
extern uschar *dkim_signers; /* Expansion variable, holds colon-separated list of domains and identities that have signed a message */
+extern gstring *dkim_signing_record; /* domains+selectors used */
extern uschar *dkim_signing_domain; /* Expansion variable, domain used for signing a message. */
extern uschar *dkim_signing_selector; /* Expansion variable, selector used for signing a message. */
extern uschar *dkim_verify_hashes; /* Preference order for signatures */