Origin for each line in sysctl.init.mk from check-in 7a1e7f4a58:

7a1e7f4a58 2019-10-21        arcade: sysctl: kld root
7a1e7f4a58 2019-10-21        arcade: .if exists(/etc/sysctl.conf)
7a1e7f4a58 2019-10-21        arcade: 	echo "MRC:$@> Setting sysctl defaults."; \
7a1e7f4a58 2019-10-21        arcade: 	awk '$$0~/^[ ]*(#.*)?$$/{next}{print}' < /etc/sysctl.conf | xargs -n1 sysctl
7a1e7f4a58 2019-10-21        arcade: .endif