diff --git a/src/Makefile b/src/Makefile
index d6f2972..e8f1a40 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -6,7 +6,7 @@ VPATH += $(HOST)
 
 BUILDDATE := `date +"%Y%m%d"`
 
-CFLAGS = -Wall -Wextra -Wno-pointer-sign -Wno-char-subscripts\
+CFLAGS += -Wall -Wextra -Wno-pointer-sign -Wno-char-subscripts\
 	-O0 -std=gnu99 -g3 -DBUILDDATE=\"$(BUILDDATE)\"\
 	-I. -Iinclude -I$(HOST)
 
diff --git a/src/linux/Makefile.inc b/src/linux/Makefile.inc
index 0968764..48793ec 100644
--- a/src/linux/Makefile.inc
+++ b/src/linux/Makefile.inc
@@ -1 +1 @@
-LDFLAGS = -lftdi
+LDFLAGS += -lftdi