security/libressl-devel features the new LibreSSL 2.7, which introduced compatibility with most of OpenSSL 1.1 and 1.0.2 APIs. As it stands, this software misdetects and mishandles LibreSSL >= 2.7.
FreeBSD patches will be on Phabricator shortly. Additionally, I've submitted these fixes upstream.
Upstream merged the changes https://github.com/lsh123/xmlsec/pull/167
security/xmlsec1: Fix build with LibreSSL 2.7
- LibreSSL 2.7 implements most of OpenSSL 1.1 API
Submitted by: Charlie Li <ml+freebsd vishwin info>
Approved by: maintainer time-out
Obtained from: https://github.com/lsh123/xmlsec/pull/167
Differential Revision: https://reviews.freebsd.org/D14851