minimal fix to build with --shuffle and -j1
--- a/sys/unix/Makefile.top
+++ b/sys/unix/Makefile.top
@@ -273,7 +273,7 @@ title.img:
 check-dlb: options
 	@if egrep -s librarian dat/options ; then $(MAKE) dlb ; else true ; fi
 
-dlb:
+dlb: $(VARDATD) spec_levs
 	( cd util ; $(MAKE) dlb )
 	( cd dat ; LC_ALL=C ; ../util/dlb cf nhdat $(DATDLB) )