[openssl/openssl] b484c6: Disable atomic refcounts with no-threads

[jwt27]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: b484c6268ce38ccbc1bf5ee95bbd36f76fba994f
      https://github.com/openssl/openssl/commit/b484c6268ce38ccbc1bf5ee95bbd36f76fba994f
  Author: J.W. Jagersma <jwjagersma at gmail.com>
  Date:   2022-11-25 (Fri, 25 Nov 2022)

  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)