It's kinda sad these headers won't be released by AMD as I'm pretty sure there'll be some unofficial ones buzzing around soon. Seems a rather bizarre decision as the various mantle DLLs are already in the AMD drivers and the specification gives all details of the API.
It's be fantastic to be able to play around with Mantle before Vulcan appears.....
@computerquip If you do start to put together some headers it'd be great to see them posted!!!