Append $(DESTDIR) to all $(bindir), $(datadir) and $(mandir). Got 
this patch from OE commit id 709c4d66e0b107ca606941b988bad717c0b45d9b

Upstream-Status: Inappropriate [not author]

Index: dbench-3.04/Makefile.in
===================================================================
--- dbench-3.04.orig/Makefile.in	2006-09-17 20:21:07.000000000 +0200
+++ dbench-3.04/Makefile.in	2006-09-17 20:21:36.000000000 +0200
@@ -32,12 +32,12 @@
 
 # Careful here: don't install client.txt over itself.
 install: all
-	${INSTALLCMD} -d $(bindir) $(datadir) $(mandir)
-	${INSTALLCMD} dbench tbench tbench_srv $(bindir)
-	${INSTALLCMD} client.txt $(datadir)
-	${INSTALLCMD} -m644 dbench.1 $(mandir)
-	ln -sf dbench.1 $(mandir)/tbench.1
-	ln -sf dbench.1 $(mandir)/tbench_srv.1
+	${INSTALLCMD} -d $(DESTDIR)$(bindir) $(DESTDIR)$(datadir) $(DESTDIR)$(mandir)
+	${INSTALLCMD} dbench tbench tbench_srv $(DESTDIR)$(bindir)
+	${INSTALLCMD} client.txt $(DESTDIR)$(datadir)
+	${INSTALLCMD} -m644 dbench.1 $(DESTDIR)$(mandir)
+	ln -sf dbench.1 $(DESTDIR)$(mandir)/tbench.1
+	ln -sf dbench.1 $(DESTDIR)$(mandir)/tbench_srv.1
 
 clean:
 	rm -f *.o *~ dbench tbench tbench_srv
