socket.gethostbyaddr does not work with IPv6 on Solaris

Bug report

Bug description:

The documentation suggests that socket.gethostbyaddr supports both IPv4 and IPv6:
https://docs.python.org/3/library/socket.html#socket.gethostbyaddr
however, gethostbyaddr_r on Solaris does not support IPv6.

Solaris/Illumos provide platform-specific getipnodebyaddr function which can be used to lookup IPv6 addresses.

I did not test this with Illumos, but the man page suggest the same behavior as with Oracle Solaris:
https://www.smartos.org/man/3nsl/gethostbyaddr_r

"the functions described in the following cannot be used with applications targeted to work with IPv6."

CPython versions tested on:

CPython main branch, 3.13, 3.11

Operating systems tested on:

Other

Linked PRs

• gh-157498

socket.gethostbyaddr エントリポイントから始め、Solaris 上で CPython が gethostbyaddr_r をどのように呼び出しているかを確認します。Issue で説明されているプラットフォーム固有の getipnodebyaddr の動作とその経路を比較し、リンクされた PR gh-157498 を確認します。Solaris で IPv6 の逆引きが、既存の IPv4 の動作を壊すことなく機能すれば完了です。