On Mon, Sep 13, 2021 at 04:38:29PM -0700, Raghavendra Rao Ananta wrote:

> I was looking into this though and could only find some utilities such
> as tools/iio/, tools/spi/, and so on, which seem to create a symbolic
> link to the header present in the kernel (rather than copying). Is
> this what you were referring to?

TBH I'm not exactly aware of how it works, just that it does work - the
main case I was thinking of was the uapi headers, mainly when used in
kselftest.  Those look like they're actual copies rather than symlinks
so I guess it's a different mechanism to what's used by the other tools
you found.