diff -uNr old-vpcs-0.8/src/Makefile.linux vpcs-0.8/src/Makefile.linux

--- old-vpcs-0.8/src/Makefile.linux	2015-11-20 15:00:32.000000000 +0100

+++ vpcs-0.8/src/Makefile.linux	2015-11-20 15:01:44.000000000 +0100

@@ -4,8 +4,8 @@

 CPUTYPE:=$(shell uname -m)

 HVOPT=-DHV

-CFLAGS=-D$(OSTYPE) -D$(CPUTYPE) $(HVOPT) -Wall -DTAP

+CFLAGS:=$(CFLAGS) -D$(OSTYPE) -D$(CPUTYPE) $(HVOPT) -Wall -DTAP

 LDFLAGS=-lpthread -lutil

 OBJS=vpcs.o \

 	daemon.o \

 	readline.o \