[openssl/openssl] cdcb9c: Disable atomic refcounts with no-threads

[jwt27]

  Branch: refs/heads/openssl-3.1
  Home:   https://github.com/openssl/openssl
  Commit: cdcb9c76bddc36ace7d06bf0a97935f2ff1b67a8
      https://github.com/openssl/openssl/commit/cdcb9c76bddc36ace7d06bf0a97935f2ff1b67a8
  Author: J.W. Jagersma <jwjagersma at gmail.com>
  Date:   2023-03-01 (Wed, 01 Mar 2023)

  Changed paths:
    M include/internal/refcount.h

  Log Message:
  -----------
  Disable atomic refcounts with no-threads

This is needed for building with '-march=i386 no-threads', on platforms
where libatomic is not available (djgpp, specifically).  The
implementation now falls back to 'CRYPTO_atomic_add()', which performs
plain lock-free addition in a 'no-threads' build.

Reviewed-by: Matt Caswell <matt at openssl.org>
Reviewed-by: Paul Dale <pauli at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19751)
(cherry picked from commit b484c6268ce38ccbc1bf5ee95bbd36f76fba994f)