--- Makefile.in
+++ Makefile.in
@@ -3,6 +3,8 @@
 
 srcdir = @srcdir@
 VPATH = @srcdir@
+bindir = @bindir@
+mandir = @mandir@
 
 VERSION = @RELEASE_VERSION@
 INSTALL = @INSTALL@
@@ -26,9 +28,9 @@
 	nroff -man setserial.8 > setserial.cat
 
 install: setserial setserial.8
-	$(INSTALL_PROGRAM) setserial $(DESTDIR)/bin
-	$(STRIP) $(DESTDIR)/bin/setserial
-	$(INSTALL_DATA) setserial.8 $(DESTDIR)/usr/man/man8
+	$(INSTALL_PROGRAM) setserial $(DESTDIR)$(bindir)
+	$(STRIP) $(DESTDIR)$(bindir)/setserial
+	$(INSTALL_DATA) setserial.8 $(DESTDIR)$(mandir)/man8
 
 clean:
 	$(RM) setserial setserial.o setserial.cat *~