Move the env whitelists to an rc var and build in the system whitelist.

etc/rc.conf

@@ -52,6 +52,10 @@ rc_force_auto="NO"
 # /var/log/rc.log
 rc_logger="NO"
 
+# By default we filter the environment for our running scripts. To allow other
+# variables through, add them here. Use a * to allow all variables through.
+# rc_env_allow="VAR1 VAR2"
+
 ##############################################################################
 # MISC CONFIGURATION VARIABLES
 # There variables are shared between many init scripts