Add support for building Luajit2 on Windows ARM64EC

[MugundanMCW]

PR Description:

• ARM64EC is a Windows on ARM ABI that enables native ARM64 execution while maintaining interoperability with x64 code through emulation, making it useful for applications that depend on x64 plugins.

• The patch adds Windows ARM64EC support to LuaJIT project. The implementation is based on prior ARM64EC compatibility work by corsix for LuaJIT.

• The changes have been validated by successfully building LuaJIT on Windows ARM64, and the generated binaries correctly target the ARM64EC architecture.

• ⁠This PR is part of the Windows ARM64EC enablement effort discussed with Yichun Zhang. As Per the discussion, OpenResty has welcomed a PR against their LuaJIT2 repository and is open to collaborating on this work going forward.

cc: @Psychlist1972 @mayankag-qti

[Psychlist1972]

Hi all. We're new to this repo, so please let us know if there are steps we should take when submitting a PR to assist with review and merge. Not sure if we should tag someone for review here.

@agentzh any advice?

Thanks!

Pete
Microsoft

[Psychlist1972]

Contacted Yichun today via email to see if there's anything else we should do to help the PR move forward.

Pete
Microsoft

[Psychlist1972]

Hi All. I see the build is failing, but it's failing on Linux, not Windows. @MugundanMCW is that due to your PR or unrelated?

Is gcc on Linux being used to create a Windows Arm64EC build? It looks like it from the configuration, but perhaps I'm misreading.

Pete
Microsoft

[MugundanMCW]

Hi @Psychlist1972,

I don't think the CI failures are caused by my patch, as I noticed that the CI checks for other PRs are also currently failing.

Regarding the Windows ARM64EC build, we have msbuild.bat , which can be used to build ARM64EC binaries on Windows ARM devices using the MSVC compiler.

Thanks!