Update macOS compilers to Xcode 26.6. For GHA builds: - macOS aarch64: bump the runner to `macos-26` - macOS x64: leave the running at `macos-15-intel` (which is our earlier-stated terminal version), meaning we will use Xcode 26.3, which is the latest one supported on the `macos-15-intel` runner.
In addition to bumping the version, we added a new optional `metalToolchainDir` property (defaults to using `toolchainDir`) to allow for the fact that Apple has made the Metal toolchain an optional download that installs in a separate directory. --------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - 8393943: Update to Xcode 26.6 on macOS Changes: https://git.openjdk.org/jfx/pull/2355/files Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=2355&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8393943 Stats: 19 lines in 4 files changed: 8 ins; 0 del; 11 mod Patch: https://git.openjdk.org/jfx/pull/2355.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/2355/head:pull/2355 PR: https://git.openjdk.org/jfx/pull/2355
