--- Makefile.osx.orig	2019-03-02 18:21:21.000000000 -0800
+++ Makefile.osx	2019-03-02 18:22:40.000000000 -0800
@@ -1,11 +1,11 @@
 RM=rm -f
-CC=gcc $(CCOPT)
+CC ?= gcc $(CCOPT)
 OSTYPE=Darwin
 CPUTYPE=i386
 HVOPT=-DHV
 
-CFLAGS=-D$(OSTYPE) -D$(CPUTYPE) $(HVOPT) -Wall
-LDFLAGS=-lpthread
+CFLAGS += -D$(OSTYPE) -D$(CPUTYPE) $(HVOPT) -Wall
+LDFLAGS += -lpthread
 OBJS=vpcs.o \
 	daemon.o \
 	readline.o \