diff --git a/Makefile b/Makefile
index 6bfe9ee..61ab749 100644
--- a/Makefile
+++ b/Makefile
@@ -10,7 +10,7 @@ SHAREDIR=$(PREFIX)/share/$(PROGNAME)
 EXTRACFLAGS=-DHTMLPATH=\"$(SHAREDIR)\"
 endif
 
-CFLAGS=-O2 -g -Wall -W `pkg-config --cflags librtlsdr`
+CFLAGS+=-O2 -g -Wall -W `pkg-config --cflags librtlsdr`
 LIBS=`pkg-config --libs librtlsdr` -lpthread -lm
 CC=gcc
 
@@ -18,7 +18,7 @@ CC=gcc
 all: dump1090 view1090
 
 %.o: %.c
-	$(CC) $(CFLAGS) $(EXTRACFLAGS) -c $<
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(EXTRACFLAGS) -c $<
 
 dump1090: dump1090.o anet.o interactive.o mode_ac.o mode_s.o net_io.o
 	$(CC) -g -o dump1090 dump1090.o anet.o interactive.o mode_ac.o mode_s.o net_io.o $(LIBS) $(LDFLAGS)