--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,8 @@ INSTALL = install
 # APIVERSION is used in soname
 APIVERSION = 1
 #LDFLAGS = -Wl,--no-undefined
-CFLAGS = -O -fPIC -Wall -DENABLE_STRNATPMPERR
+COPTS = -O
+CFLAGS = $(COPTS) -fPIC -Wall -DENABLE_STRNATPMPERR
 
 LIBOBJS = natpmp.o getgateway.o