add readme to prepare target

Author: segasai

Makefile

@@ -48,7 +48,7 @@ readme:
 dump.c: prepare
 	./prepare
 
-prepare: prepare.o q3cube.o q3c_poly.o
+prepare: prepare.o q3cube.o q3c_poly.o readme
 	$(CC) $? $(CFLAGS) $(PG_LIBS) $(PG_LDFLAGS) $(LDFLAGS) $(MYBINLIBS) -o $@
 
 gen_data: gen_data.c