[patch rfc]: use xxhash() in ld build-id computation, incl. benchmark

[Frank Ch. Eigler]

Hi -

On Fri, Sep 20, 2024 at 07:04:20PM +0200, Mark Wielaard wrote:
> [...]
> I think you want to explicitly test for XXH3_createState (or any other
> XXH3/XXH128 function introduced in 0.8.0. Previous versions might have
> XXH32, but not XXH3/XXH128 support.

Sure.

> Is the result a integral value or a byte array? [...]
> Or maybe always use big or little endian encoding to get consistent
> results even when the runtime endianness and the file endianness are
> different? I note there is XXH128_canonicalFromHash.

Yeah, seems like a canonicalFromHash call is appropriate, as
cross-arch linking is reasonable in binutils.  Will add that.

- FChE