Re: bitops.h ifdef __KERNEL__ cleanup.

["H. Peter Anvin" <hpa@zytor.com>]

Followup to:  <11472.995579612@redhat.com>
By author:    David Woodhouse <dwmw2@infradead.org>
In newsgroup: linux.dev.kernel
> 
> It has been stated many times that kernel headers should not be used in
> apps. Renaming or moving them should not be necessary - and people would
> probably only start to use them again anyway. We'd see autoconf checks to 
> find whether it's linux/private.h or xunil/private.h :)
> 
> In the absence of any expectation that userspace developers will ever obey
> the simple and oft-repeated rule that you don't use kernel headers from
> userspace, the #ifdef __KERNEL__ approach would seem to be the best on
> offer.
> 

Note that the rule is at least in part theoretical; even glibc include
kernel headers or -derivatives.

I think the idea with <asm/bitops.h> is that they are protected by
#ifdef __KERNEL__ if they are kernel-only; however, if they work in
user space then there is no #ifdef and autoconf can detect their
presence.

	-hpa
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