added /sbin in mtree

/usr/etc/rc now reads variables from /usr/etc/rc.local it can feed to
drivers as args

etc/mtree/minix.tree

@@ -1,5 +1,6 @@
 755 root    operator /
 755 bin     operator /bin
+755 bin     operator /sbin
 755 root    operator /dev
 755 root    operator /etc
 755 root    operator /lib

etc/usr/rc

@@ -1,6 +1,7 @@
 # /usr/etc/rc - continued system initialization.
 
 RANDOM_FILE=/usr/adm/random.dat
+LOCAL_FILE=/usr/etc/rc.local
 
 case "$#:$1" in
 1:start|1:stop|1:down)
@@ -10,6 +11,10 @@ case "$#:$1" in
     exit 1
 esac
 
+if [ -f "$LOCAL_FILE" ]
+then	. "$LOCAL_FILE" $1
+fi
+
 disabled()
 {
     ifs="$IFS"; IFS=,
@@ -91,7 +96,8 @@ start)
     do
         if grep " $driver " /etc/inet.conf > /dev/null 
         then 
-            up $driver 
+            eval arg=\$${driver}_arg
+            up $driver "$arg"
         fi
     done
     up inet ""