--- Makefile.orig	2016-03-23 12:05:46 UTC
+++ Makefile
@@ -1,19 +1,18 @@
 OBJS := $(patsubst %.cpp,%.o,$(wildcard src/*.cpp src/hqx/*.cpp))
 
-DESTDIR = 
-PREFIX  = /usr/local
+PREFIX  ?= /usr/local
 DATADIR = $(PREFIX)/share
 BINDIR  = $(PREFIX)/bin
 ICONDIR  = $(DATADIR)/pixmaps
 APPDIR  = $(DATADIR)/applications
 
-CXX = g++
+CXX ?= g++
 
-CXXFLAGS = -Wall -std=c++98 -pedantic `sdl-config --cflags` -pipe
-all   : CXXFLAGS += -O2 -s -DNDEBUG -fno-threadsafe-statics -march=native -fomit-frame-pointer -ffast-math -fno-exceptions -fno-rtti
-debug : CXXFLAGS += -O0 -g
+all   : CXXFLAGS ?= -pipe -O2 -s -DNDEBUG -fno-threadsafe-statics -march=native -fomit-frame-pointer -ffast-math -fno-exceptions -fno-rtti
+debug : CXXFLAGS ?= -pipe -O0 -g
+CXXFLAGS += -Wall -std=c++98 -pedantic `sdl-config --cflags`
 
-LDFLAGS = `sdl-config --libs` -lSDL_image -lSDL_net
+LDFLAGS += `sdl-config --libs` -lSDL_image -lSDL_net
 
 # lto is supported in g++ version 4.5.0 or higher
 CXX_MAJOR := $(shell $(CXX) -dumpversion | cut -d'.' -f1)