Apple Headers README
To make this compile, you may need to get the latest headers from Apple. They are avaiable for free under an open source license, but I haven't invested the time to read through the license and understand its terms for redistribution--that's why I haven't included them. The file you will want to download is IOHIDFamily-86.26.tgz from the 10.3.8 release of Darwin. Once you download it, place these two headers in this directory structure:
apple-headers
|--IOKit
|--hidsystem
|--ev_keymap.h
|--IOHIDSystem.h
This may not be necessary in the future. Mac OS X might have them installed with the Developer Tools at some later date.