mail/cclient: Unbreak in 11.4 and 12.2

Dimitry sent a more generic patch that workarounds the problem in mail/cclient
instead of its consumers.

Related to r554904.

PR: 250740
Submitted by: dim@FreeBSD.org
Reported by: colin@fbug.ksac.uk
MFH: 2020Q4 (blanket, build fix)