Usually, these FD-files belong to the SDKs (software development kits) of the libraries. For the AmigaOS it's the NDK with the Includes and you can find it here:
http://os.amigaworld.de/index.php?lang=en&page=1 or more exactly here:
http://os.amigaworld.de/download.php?id=3
I'm sorry pintcat, but atm I can't find the utilities for generating FD-files or the documentation at least.