--- a/Makefile	2017-10-29 08:39:34.209474792 +0200
+++ b/Makefile	2017-10-29 15:11:02.082490459 +0200
@@ -2,8 +2,7 @@
 #EXTRAVERSION=-pre1
 CC = gcc -Wall
 #OPT = -g -O0
-OPT = -O3
-CFLAGS = $(OPT) $(NOIPV6)
+CFLAGS += $(OPT) $(NOIPV6)
 LIBS = 
 ifneq ($(NOIPV6),)
 APPEXTV6=-noipv6
@@ -53,7 +52,7 @@
 #	$(MAKE) CC=icc OPT="-w -O3 -parallel -unroll -align -xM -vec_report -par_report2"
 
 $(APP)$(EXTRAVERSION)$(APPEXT): $(APP)$(EXTRAVERSION).c $(LIBS)
-	$(CC) $(CFLAGS) -o $@ $< $(LIBS)
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) -o $@ $< $(LIBS)
 inet_ntop.o: missing/inet_ntop.c missing/config.h
 	$(CC) $(CFLAGS.MISSING) -o $@ -c $<
 inet_pton.o: missing/inet_pton.c missing/config.h