Mac OS X 10.4 (Tiger)'s copyfile()
All of the snazzy ACL-and-metadata-copying features in Darwin 8 / Tiger live in one function, copyfile(). Unfortunately, Apple forgot to include the header for it in the version of Xcode that ships with Mac OS X 10.4.
Since this isn't a static library, and probably depends on New Stuff, using it in a backwards compatible way (i.e. to get resource-fork copying in Panther) probably isn't going to work. Oh well.