--- Makefile.orig	2014-07-10 23:43:16.837117715 +0800
+++ Makefile	2014-07-10 23:43:35.518127751 +0800
@@ -33,8 +33,8 @@ opt: $(ML)
 	ocamlopt -o cppo -dtypes unix.cmxa $(ML)
 
 install:
-	install -m 0755 cppo $(BINDIR) || \
-		install -m 0755 cppo.exe $(BINDIR)
+	install -m 0755 cppo $(DESTDIR)$(BINDIR) || \
+		install -m 0755 cppo.exe $(DESTDOR)$(BINDIR)
 
 cppo_version.ml: Makefile
 	echo 'let cppo_version = "$(VERSION)"' > cppo_version.ml