RFR: 8277489: Rewrite JAAS UnixLoginModule with FFM [v2]

[Martin Doerr]

On Mon, 22 Dec 2025 14:47:41 GMT, Weijun Wang <weijun at openjdk.org> wrote:

>> Rewrite the native calls with FFM.
>
> Weijun Wang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   rewrite without jextract

src/jdk.security.auth/share/classes/com/sun/security/auth/module/UnixSystem.java line 83:

> 81:     private static final ValueLayout.OfLong C_LONG
> 82:             = (ValueLayout.OfLong) LINKER.canonicalLayouts().get("long");
> 83: 

These functions are probably always fast and never block, right?
If so, we could use `Linker.Option.critical` to make the calls faster if performance is important.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/28931#discussion_r2657727804