iproute2: don't lose LDFLAGS.

Unbreaks creating veth devices, also see
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=674847

srcpkgs/iproute2/template

@@ -1,7 +1,7 @@
 # Template file for 'iproute2'
 pkgname=iproute2
 version=4.1.1
-revision=1
+revision=2
 build_pie=yes
 hostmakedepends="pkg-config perl flex"
 makedepends="libfl-devel libmnl-devel db-devel iptables-devel"
@@ -22,6 +22,7 @@ checksum=73077a989efb934450bd655cbd9aaddaa747cb696c64d0c9a3323768a6a8e66f
 do_configure() {
 	./configure
 	sed -i 's,CCOPTS,HOSTCCOPTS,g' netem/Makefile
+	sed -i 's/^LDFLAGS +=/override &/' */Makefile
 }
 do_build() {
 	make HOSTCC=cc CC="$CC" RANLIB="$RANLIB" AR="$AR" LD="$LD" \