--- a/Makefile	2018-11-04 13:26:07.744752852 -0700
+++ b/Makefile	2018-11-04 13:27:46.074222441 -0700
@@ -1,25 +1,26 @@
-CFLAGS=-O3 --std=gnu++11
-LFLAGS=-s -lpng
+CFLAGS+= -O3 --std=gnu++11
+LFLAGS+= -s -lpng
 SRCD = source
 SRC = $(wildcard $(SRCD)/*.cpp)
 OBJD = obj
 OBJ = $(patsubst $(SRCD)/%.cpp,$(OBJD)/%.o,$(SRC))
 TSTD = tests
-INSTALL_PATH=/usr/local
+PREFIX?=/usr/local
+target=$(DESTDIR)$(PREFIX)
 
 $(shell mkdir -p $(OBJD) >/dev/null)
 
 bfk: $(OBJD) $(OBJ)
 	@echo Linking: $@
-	@g++ -o bfk $(OBJ) $(LFLAGS)
+	@$(CXX) -o bfk $(OBJ) $(LFLAGS)
 
 $(OBJD)/%.o: $(SRCD)/%.cpp
 	@echo Compiling: $(<F)
-	@g++ $(CFLAGS) -c -o $@ $<
+	@$(CXX) $(CFLAGS) -c -o $@ $<
 
 $(OBJD)/%.d: $(SRCD)/%.cpp
 	@set -e; rm -f $@; \
-	g++ --std=gnu++11 -MM -MT $(OBJD)/$(*F).o $(CPPFLAGS) $< > $@.$$$$; \
+	$(CXX) --std=gnu++11 -MM -MT $(OBJD)/$(*F).o $(CPPFLAGS) $< > $@.$$$$; \
 	sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@.$$$$ > $@; \
 	rm -f $@.$$$$
 
@@ -34,10 +35,10 @@
 	@$(MAKE) --silent -C $(TSTD)/ clean
 
 install: bfk
-	@install -m 0755 bfk $(INSTALL_PATH)/bin/
+	@install -m 0755 bfk $(target)/bin
 
 remove:
-	@rm -fv $(INSTALL_PATH)/bin/bfk
+	@rm -fv $(target)/bin/bfk
 
 test: bfk
 	@sync bfk