Proposal: Separate build and target architecture in the build scripts

[adamfarley]

Summary

To separate the concepts of build (verb) and target architectures in the build scripts.

Value

This change will:

• Ensure the SBOM always uses the correct architecture for cross-compiled builds.
• Ensure the static libs folder always has the correct name for cross-compiled builds.
• Create a more robust build framework for cross-compilation.

Glossary

"Build architecture" - The architecture of the machine we're building a JDK binary on.

"Target architecture" - The architecture of the machine we're building a JDK binary for.

Details

In this issue for Mac x64, we discovered that the target architecture is, in many ways, conflated with the build architecture.

We added a temporary work-around for the issue here, but in the long run we need to be considering these architectures separately in order to provide a robust framework for generating cross-compiled builds.

A good place to start is this line of code. We should make sure this variable is suitably renamed (build_arch), and is never accidentally used for the target architecture. The target architecture should be set by the job parameter, which should also be renamed (e.g. TARGET_ARCH) for clarity.

Useful information.