luajit2: add riscv64 support

[BKPepe]

Maintainer: @jmarcet
Compile tested: will be done inside CI/CD
Run testing: NO, since I do not have riscv64 device.

This adds support RISC-V64 to luajit2 by backporting https://redirect.github.com/openresty/luajit2/pull/236

Fixes: #27611

[Copilot]

Pull request overview

This PR aims to add RISC-V64 architecture support to the luajit2 package by backporting changes from openresty/luajit2#236. The change updates the architecture configuration to include riscv64 in the list of supported platforms.

Key Changes:

• Added riscv64 to the HAS_LUAJIT_ARCH configuration option in the Makefile

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[Copilot]

Adding riscv64 to the HAS_LUAJIT_ARCH configuration without including the necessary patches for RISC-V64 support will likely cause build failures. The PR description mentions backporting https://redirect.github.com/openresty/luajit2/pull/236, but no corresponding patch files are present in the patches directory. The actual RISC-V64 support patches need to be added to lang/lua/luajit/patches/ before enabling this architecture in the configuration.

Suggested change

	default y if i386||x86_64||arm||armeb||aarch64||powerpc||mips||mipsel||mips64||riscv64
	default y if i386||x86_64||arm||armeb||aarch64||powerpc||mips||mipsel||mips64

[BKPepe]

Okay, I see that riscv64 is now compiled for luajit2, but it fails for luajit and that is why it is failing in the CI/CD check. We need that logic, but that can be done later. Merging.