diff --git a/hmmlib/makefile b/hmmlib/makefile
index 5450a14..d83f0a0 100644
--- a/hmmlib/makefile
+++ b/hmmlib/makefile
@@ -3,6 +3,9 @@ all: hmml.a example
 hmml.a: hmmlib.o
 	ar rcs $@ $<
 
+hmmlib.c: hmmlib.l
+	lex -t $< > $@
+
 hmmlib.o: hmmlib.c
 	gcc -std=gnu99 -D_GNU_SOURCE -g -c $< -o $@
 
@@ -10,6 +13,6 @@ example: example.c hmml.a
 	gcc -std=gnu99 -g $^ -o $@
 	
 clean:
-	$(RM) hmml.a hmmlib.o example
+	$(RM) hmml.a hmmlib.o hmmlib.c example
 
-.PHONY: clean
+.PHONY: all clean