diff --git a/util/ack/Makefile b/util/ack/Makefile
index 53409a61..fa3d466d 100644
--- a/util/ack/Makefile
+++ b/util/ack/Makefile
@@ -11,7 +11,7 @@ FE=fe
 INTABLES=pdp int
 LNTABLES=acc apc abc ocm vax4 i86 m68k2 m68k4 pmds pmds4 mantra \
 	m68020 z8000 int22 int24 int44 6500 6800 6805 6809 i80 ns s2650 z80 \
-	sun3 sun2
+	sun3 sun2 xenix3
 INCLUDES=-I$(EMHOME)/h
 CFLAGS=-O $(INCLUDES)
 LDFLAGS=-i