git: rc.subr: Add list_vars() function

[Aaron LI]

commit 53085f893f0d9438dbaf403f947403c5e6c9665c
Author: Aaron LI <***@aaronly.me>
Date: Tue Nov 6 04:31:38 2018 +0800

rc.subr: Add list_vars() function

Taken-from: FreeBSD

Summary of changes:
etc/rc.subr | 13 +++++++++++++
1 file changed, 13 insertions(+)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/53085f893f0d9438dbaf403f947403c5e6c9665c