Publish Android arm64 LTO artifact

[matthargett]

Publish Android arm64 LTO artifact
https://bugs.webkit.org/ — N/A; this changes oven-sh/Bun release packaging only, not upstream WebKit behavior.

Reviewed by NOBODY (OOPS!).

BabylonNative previously consumed the jsc-android-buildscripts package maintained by the React Native community, but that project and package have been abandoned. Using Bun's JSC instead keeps the JavaScriptCore build aligned with another actively maintained JavaScript runtime.

Bun's current prebuiltSuffix() already resolves Android arm64 + LTO to bun-webkit-linux-arm64-android-lto.tar.gz, but the WebKit release workflow does not currently produce that asset. Downstream embedders therefore have to use the native Android archive. BabylonJS/JsRuntimeHost#206 does that on Android while consuming Bun's LTO archive on Linux.

Add an Android arm64 Release/LTO lane using the same full-LTO and whole-program-vtable flags as the Linux arm64 LTO artifact. The Android build scripts already pass LTO_FLAG through target ICU and WebKit compilation with LLVM 21, so the remaining work is to add the matrix entry and publish its archive. Existing Android arm64/x64 native and debug artifacts remain unchanged.

Only arm64 LTO is added. The large ICU and WebKit build directories remain tmpfs-backed, and the release runner continues to handle only the compressed artifact. The resulting bitcode must be final-linked with LLVM/LLD 21. Bun's Android cross-build already does that; consumers using an NDK-provided linker need a matching LLVM version. A possible follow-up is to build this artifact with the Android NDK toolchain for consumers such as BabylonNative.

Validation performed:

• actionlint parses the modified workflow after excluding the repository's existing custom-runner and unrelated baseline diagnostics.
• bash -n android-release.sh
• shellcheck android-release.sh
• Matrix and artifact-name assertions against the parsed workflow.
• git diff --check

A full artifact build requires a maintainer-triggered Preview Build because the repository intentionally rejects automatic preview runs from external PR authors.

• .github/workflows/build-reusable.yml:
  Add the Android arm64 Release/LTO matrix entry, forward its LTO_FLAG, and download, rename, and upload bun-webkit-linux-arm64-android-lto.tar.gz with the other Android release assets.

[claude]

Claude Code Review

This pull request is from a fork — automated review is disabled. A repository maintainer can comment @claude review to run a one-time review.

[coderabbitai]

Walkthrough

Changes

Android LTO artifact

Layer / File(s)	Summary
Build matrix and LTO invocation .github/workflows/build-reusable.yml	The linux-android matrix adds an arm64 Android LTO variant, and the build command passes its LTO_FLAG to android-release.sh.
Release artifact packaging .github/workflows/build-reusable.yml	The release job downloads, renames, and includes the Android LTO archive in the final asset list.

🚥 Pre-merge checks | ✅ 3 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description covers the change and validation, but it does not follow the template's required Bugzilla bug link/ID and commit-message structure.	Add the bug title and Bugzilla bug ID/link, and format the description to match the repository template, including the required explanatory section and file list.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title accurately summarizes the main change: publishing the Android arm64 LTO artifact.

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[matthargett]

Updated the description to the repository commit-message template. The Bugzilla field is explicitly N/A because this is oven-sh/Bun release-workflow packaging rather than an upstream WebKit behavior change; the Reviewed-by and per-file sections are now present. @coderabbitai review

[coderabbitai]

@matthargett Thanks for updating the description — noted on the Bugzilla N/A rationale and the added Reviewed-by/per-file sections. I'll kick off a fresh review of the changes now.

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