The current rc.d script is intended to allow one to change the config path, however, it doesnt seem to be reading the rc.conf, atleast not in 10.1 where I tested. Attaching patch that fixes that.
Hi, Due to an issue with the backend FreeBSD Bugzilla database, your original PR and any updates to it since have been lost. I've recreated the original PR as best as I can, however any attachments and updates you submitted to the PR have been lost. Please could you resubmit them? Thanks, and apologies.
Created attachment 151494 [details] Patch for proftpd.in Re-uploading patch after bugzilla crash
A commit references this bug: Author: mm Date: Sun Feb 1 22:25:51 UTC 2015 New revision: 378282 URL: https://svnweb.freebsd.org/changeset/ports/378282 Log: Fix mirror sites [1] Compile with -pthread if using base OpenSSL [2] Fix rc script [3] PR: 191011 [1], 195921 [2], 196635 [3] Changes: head/ftp/proftpd/Makefile head/ftp/proftpd/files/proftpd.in