[RFC] Splitting kernel headers and deprecating __KERNEL__

[David Howells]

> I'm not particularly stuck on the <user/> namespace.  We could invent
> a better name.  How about <kern/> and <arch/> to replace <linux/>
> and <asm/>?  Obviously keeping linux/ and asm/ symlinks for backwards
> compatibility.

I'd rather not change linux and asm within the kernel itself. We'd have to
patch pretty much every file and move all the include files around. That's a
lot of patch.

How about calling the interface headers "kapi*/" instead of "user*/". In case
you haven't guessed, "kapi" would be short for "kernel-api".

Then we'd have in the kernel:

	NEW DIRECTORY		DIRECTORY SHADOWED
	=============		==================
	include/kapi/		include/linux/
	include/kapi-*/		include/asm-*/
	include/kapi-rxrpc/	include/rxrpc/
	include/kapi-net/	include/net/

And in userspace:

	SOURCE			INSTALLED AS
	======================	============
	include/kapi/		/usr/include/kapi/
	include/kapi-i386/	/usr/include/kapi-i386/
	include/kapi-generic/	/usr/include/kapi-generic/
				/usr/include/linux -> kapi
				/usr/include/asm -> kapi-i386
				/usr/include/asm-generic -> kapi-generic (?)

David