$NetBSD: patch-Makefile,v 1.1 2017/07/13 12:16:27 wiz Exp $

Honor CXXFLAGS and LDFLAGS.

--- Makefile.orig	2017-07-13 12:05:54.572398200 +0000
+++ Makefile
@@ -1,7 +1,7 @@
 CFLAGS=-ggdb
 GTK=3.0
-CXXFLAGS=$(CFLAGS) `sdl-config --cflags` `pkg-config gtk+-${GTK} --cflags`
-LDFLAGS=`sdl-config --libs` `pkg-config gtk+-${GTK} --libs`
+CXXFLAGS+=$(CFLAGS) `sdl-config --cflags` `pkg-config gtk+-${GTK} --cflags`
+LDFLAGS+=`sdl-config --libs` `pkg-config gtk+-${GTK} --libs`
 
 sfxr: main.cpp tools.h sdlkit.h
 	$(CXX) $< $(CXXFLAGS) $(LDFLAGS) -o $@