[exim] unknown variable name "tls_in_cipher"

Attempting to set up authentication on Debian Wheezy. Authentication is not
being advertised. Troubleshooting gives the following results:

exim -bh 127.0.0.1

**** SMTP testing session as if from host 127.0.0.1
**** but without any ident (RFC 1413) callback.
**** This is not for real!

>>> host in hosts_connection_nolog? no (option unset)
>>> host in host_lookup? yes (matched "*")
>>> looking up host name for 127.0.0.1
>>> IP address lookup yielded localhost
>>> gethostbyname2 looked up these IP addresses:
>>> name=localhost address=::1
>>> name=localhost address=127.0.0.1
>>> checking addresses for localhost
>>> ::1
>>> 127.0.0.1 OK
>>> host in host_reject_connection? no (option unset)
>>> host in sender_unqualified_hosts? no (option unset)
>>> host in recipient_unqualified_hosts? no (option unset)
>>> host in helo_verify_hosts? no (option unset)
>>> host in helo_try_verify_hosts? no (option unset)
>>> host in helo_accept_junk_hosts? no (option unset)
220 mydomain.org ESMTP Exim 4.80 Wed, 24 Jun 2015 15:53:38 -0500
ehlo me
>>> host in pipelining_advertise_hosts? yes (matched "*")
>>> host in auth_advertise_hosts? yes (matched "*")
LOG: failed to expand condition "${if eq{$tls_in_cipher}{}{}{*}}" for
plain_sasl_server authenticator: unknown variable name "tls_in_cipher"
>>> host in tls_advertise_hosts? yes (matched "*")

I'm using the Debian split config and simply uncommented the plain_sasl_server
section that is provided in the default config files:

plain_sasl_server:
driver = cyrus_sasl
public_name = PLAIN
server_realm = <short main hostname>
server_set_id = $auth1
.ifndef AUTH_SERVER_ALLOW_NOTLS_PASSWORDS
server_advertise_condition = ${if eq{$tls_in_cipher}{}{}{*}}
.endif

I'll happily post additional config files if requested but this doesn't appear
to be a config issue - it appears to be a bug. Google turns up absolutely
nothing on the error, however. Any suggestions greatly appreciated.


--
"I read the book of Job last night. I don't think God comes well out of it." -
Virginia Woolf