Add function comments.

OK sthen, deraadt

src/etc/rc

@@ -1,4 +1,4 @@
-#	$OpenBSD: rc,v 1.482 2016/05/26 16:29:51 deraadt Exp $
+#	$OpenBSD: rc,v 1.483 2016/05/27 16:49:08 rpe Exp $
 
 # System startup script run by init on autoboot or after single-user.
 # Output and error are redirected to console by init, and the console is the
@@ -158,6 +158,7 @@ make_keys() {
 	ssh-keygen -A
 }
 
+# Re-link libraries, placing the objects in a random order.
 reorder_libs() {
 	local _l _liba _libas _tmpdir _remount=false
 	local _dkdev=/dev/$(stat -L -f '%Sd' /usr/lib)
@@ -214,6 +215,8 @@ reorder_libs() {
 	echo ' done.'
 }
 
+# Run rc.* script and email output to root.
+# Usage: run_upgrade_script firsttime|sysmerge
 run_upgrade_script() {
 	local _suffix=$1
 	[[ -n $_suffix ]] || return 1