security/tor: Implemented setuid feature

[joneum]

Summary

• security/tor: Implemented setuid feature *The user should add tor_setuid=YES to /etc/rc.conf to make tor do setuid in runtime after opening the externally provided files.

PR: 218587
Reported by: xmj
Approved by: Yuri Victorovich (maintainer) xxx (mentor)
#Differential Revision: https://reviews.freebsd.org/Dxxxxx

Test Plan

~/dev/ports/security/tor % portlint -AC
WARN: Makefile: you should only use ".if ${PORT_OPTIONS:MDOCS}" to wrap installation of files into /usr/local/share/doc if the collection of files is large and it takes considerable time to copy.
WARN: Makefile: for new port, make $FreeBSD$ tag in comment section empty, to make SVN happy.
WARN: Makefile: new ports should not set PORTREVISION.
0 fatal errors and 3 warnings found.

poudriere testport:

10amd64
10i386
11amd64
11i386
12.0-CURRENT r318899 amd64
12.0-CURRENT r318400 i386