[libc-coord] Add new ABI '__memcmpeq()' to libc

[enh]

plus testing for _equality_ can (as mentioned earlier) have slightly
different properties from the three-way comparator behavior of
bcmp()/memcmp().

On Thu, Sep 16, 2021 at 2:43 PM Joseph Myers <joseph@codesourcery.com>
wrote:

> On Thu, 16 Sep 2021, James Y Knight wrote:
>
> > Wouldn't it be far simpler to just un-deprecate bcmp?
>
> The aim is to have something to which calls can be generated in all
> standards modes.  bcmp has never been part of ISO C; there's nothing to
> undeprecate there.
>
> --
> Joseph S. Myers
> joseph@codesourcery.com
>