The XMOS DFU loader is provided as source as part of the USB Audio framework, located in sc_usb_audio/module_dfu/host/xmos_dfu_osx.

The loader is compiled using libusb, the code for the loader is contained in the file xmosdfu.cpp

To build the loader a Makefile is provided, which can be run as follows:

make -f Makefile.OSX all

This Makefile contains the following:

all:
	g++ -g -o xmosdfu xmosdfu.cpp -I. -IOSX libusb-1.0.0.dylib -m32