Time to revisit bug #215197: As of security/libressl 3.1.0, the CMS API is officially supported by LibreSSL, which means p5-Crypt-SMIME is no longer broken with it.
A commit references this bug: Author: swills Date: Sat Aug 15 20:14:17 UTC 2020 New revision: 545063 URL: https://svnweb.freebsd.org/changeset/ports/545063 Log: security/p5-Crypt-SMIME can be built again with LibreSSL PR: 246374 Reported by: Peter Putzer <freebsd@mnd.sc> Changes: head/security/p5-Crypt-SMIME/Makefile
Committed, thanks!