diff --git a/Makefile b/Makefile
index 05f7ca5..2d1bda1 100644
--- a/Makefile
+++ b/Makefile
@@ -12,7 +12,7 @@ ifeq ($(OS), LINUX)  # also works on FreeBSD
 CC ?= gcc
 CFLAGS ?= -O2 -Wall
 teensy_loader_cli: teensy_loader_cli.c
-	$(CC) $(CFLAGS) -s -DUSE_LIBUSB -o teensy_loader_cli teensy_loader_cli.c -lusb $(LDFLAGS)
+	$(CC) $(CFLAGS) $(CPPFLAGS) -s -DUSE_LIBUSB -o teensy_loader_cli teensy_loader_cli.c -lusb $(LDFLAGS)
 
 
 else ifeq ($(OS), WINDOWS)