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.