[PATCH] support: add __address_diff function

[Yury Khrustalev]

On Wed, Mar 25, 2026 at 03:18:35PM +0100, Florian Weimer wrote:
> * Yury Khrustalev:
> 
> >> The #ifdef is not necessary, sysdeps overrides should work for support/
> >> headers.
> >
> > I've tried this but it doesn't seem to be working. Ideally, I want to
> > have the support_pointer_arith.c file only under sysdeps/aarch64 because
> > for all other targets the PTR_DIFF macro should be used, but makefile in
> > the support folder should probably be modified for this?
> 
> I don't know what exactly you tried to do.  I recall that it worked for
> me in the past, but I don't remember the details.  We only use sysdeps
> overrides for compilation flags today AFAICS.

I can't find any existing example of adding to 'libsupport-routines'
anywhere under 'sysdeps'. I tried doing it, and corresponding object is
not included in the libsupport static library.