iproute: DESTDIR vs LIBDIR.

Hello Rafael Almeida.

I noticed your patch adding DESTDIR support in the latest iproute2 release.
Much appreciated! Soon the debian packages might be able to move to actually
using "make install" rather then it's own installation procedure when
building packages. I've noticed something that will break though....

Debian packages usually sets DESTDIR=debian/tmp/ and packages the contents
of that directory as if it where the root file system. This will break
the /usr/lib/{tc,ip}/ module loading, because they DESTDIR (/usr) will be
/whatever-the-build-path-was/debian/tmp/lib/{tc,ip}/.
I beleive others usually call this the LIBDIR to make the separation between
DISTDIR being the (possibly temporary) place things are put when build is
done, and LIBDIR (and others) are used for actual runtime paths.

I'm attaching a patch that I think fixes this, but would be really happy if
you could have a look at to verify I'm not screwing something up.

--
Regards,
Andreas Henriksson

Signed-off-by: Stephen Hemminger <stephen.hemminger@vyatta.com>
diff --git a/Makefile b/Makefile
index cfb27f4..6096a99 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,5 @@
 DESTDIR=/usr/
+LIBDIR=/usr/lib/
 SBINDIR=/sbin
 CONFDIR=/etc/iproute2
 DOCDIR=/share/doc/iproute2
@@ -7,7 +8,7 @@
 # Path to db_185.h include
 DBM_INCLUDE:=/usr/include
 
-DEFINES= -DRESOLVE_HOSTNAMES -DDESTDIR=\"$(DESTDIR)\"
+DEFINES= -DRESOLVE_HOSTNAMES -DLIBDIR=\"$(LIBDIR)\"
 
 #options if you have a bind>=4.9.4 libresolv (or, maybe, glibc)
 LDLIBS=-lresolv