RFR: 8353009: Document target selection flag for Windows AArch64 builds

[Erik Joelsson]

On Wed, 26 Mar 2025 22:38:40 GMT, Saint Wesonga <duke at openjdk.org> wrote:

> The target selection configuration flag for Windows AArch64 should be added to the build documentation for improved discoverability and completeness.

> But is the problem that we just fails to detect the _build_ platform, and thus generates build tools for x64, instead of aarch64, which makes the build fail? (Also, why doesn't the rosetta-equivalent kick in in that case?)
> 
> Or do we also fail to set the proper target platform, so that building on windows/aarch64 will in effect be a cross compilation to x64?

If configure thinks it's running on a build platform of windows-x64, why would it try to compile for any other target than windows-x64 by default? I don't think the build fails, it just builds for the wrong platform, but as I said, I never tried this myself, this is second hand information.

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

PR Comment: https://git.openjdk.org/jdk/pull/24267#issuecomment-2766418606