A call to db_go is needed after checking for posix acl, or else the message is not displayed.

debian/alternc.config

@@ -193,7 +193,7 @@ while [ "$QUEST_STATE" != 0 -a "$QUEST_STATE" != 11 ]; do
     ACL="$(echo "$MOUNT_OPTS" | tr "," "\\n" | egrep '^acl|attr2|user_xattr$')" || true
     if [ -z "$ACL" ]; then
       db_input critical alternc/acluninstalled || true
-	    db_title AlternC
+      db_go
       db_reset alternc/acluninstalled || true
       db_fset alternc/acluninstalled "seen" "false" || true
       exit 2