--- Makefile.orig	2014-06-24 12:55:40.174706872 +0800
+++ Makefile	2014-06-24 12:55:48.621709202 +0800
@@ -11,7 +11,7 @@ INCLUDES=	-I. $(SYS_INCLUDES)
 all: $(PROGS)
 
 install: $(PROGS)
-	$(INSTALL) $(COPY) -m 0755 $(PROGS) $(PREFIX)/bin
+	$(INSTALL) $(COPY) -m 0755 $(PROGS) $(DESTDIR)$(PREFIX)/bin
 
 tcpdstat: $(OBJS)
 	$(CC) $(CFLAGS) $(INCLUDES) $(DEFINES) -o $@ $(OBJS) -lpcap -lm $(SYS_LIBS)