Fix fastboot for Darwin.

bug 16172793

Change-Id: Ib58446effc13a6e465d176da141b025d36841b8f
diff --git a/fastboot/Android.mk b/fastboot/Android.mk
index 73794a0..112bd02 100644
--- a/fastboot/Android.mk
+++ b/fastboot/Android.mk
@@ -31,6 +31,7 @@
   LOCAL_SRC_FILES += usb_osx.c util_osx.c
   LOCAL_LDLIBS += -lpthread -framework CoreFoundation -framework IOKit \
 	-framework Carbon
+  LOCAL_CFLAGS += -Wno-unused-parameter
 endif
 
 ifeq ($(HOST_OS),windows)