RFR: 8358593: Add ucontext accessors for *BSD on Aarch64

[Andrew Haley]

On Wed, 4 Jun 2025 12:58:57 GMT, snake66 <duke at openjdk.org> wrote:

> This adds macros for non-OSX BSD variants to access the required fields from ucontext_t in os_bsd_aarch64.cpp, similar to how it's already done for x86_64 in os_bsd_x86.cpp.

That looks fine, thanks. I'm not in a position to check all the BSDs, but I guess it's OK.

It's nice to see someone fixing things for BSD systems.

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Marked as reviewed by aph (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/25640#pullrequestreview-2899355731