$NetBSD: patch-Makefile,v 1.4 2016/09/19 09:17:57 fhajny Exp $

Do not overwrite LDFLAGS.

--- Makefile.orig	2015-01-20 04:12:31.000000000 +0000
+++ Makefile
@@ -1,6 +1,6 @@
 CC=cc
 CFLAGS=-O3 -Wall -Wextra
-LDFLAGS=-lz
+LDFLAGS+=-lz
 ZOPFLI=zopfli/src/zopfli/
 # use gcc and gmake on Solaris