--- Makefile.in.orig	2014-06-23 23:04:56.824141193 +0800
+++ Makefile.in	2014-06-23 23:05:12.570149447 +0800
@@ -31,9 +31,9 @@ distclean: clean
 
 install: simpleproxy
 	$(top_srcdir)/mkinstalldirs $(bindir)
-	$(INSTALL)   simpleproxy $(bindir)
+	$(INSTALL)   simpleproxy $(DESTDIR)$(bindir)
 	$(top_srcdir)/mkinstalldirs $(mandir)/man1
-	$(INSTALL)   simpleproxy.man $(mandir)/man1/simpleproxy.1
+	$(INSTALL)   simpleproxy.man $(DESTDIR)$(mandir)/man1/simpleproxy.1
 
 simpleproxy: simpleproxy.o cfg.o Makefile
 	$(CC) $(CFLAGS) -o simpleproxy simpleproxy.o cfg.o $(LIBS)