The latest version and prebuilt packages at https://github.com/WebAssembly/wasi-sdk/releases/tag/wasi-sdk-25.
Just build packages with wasip1/wasm, and do nothing on other platform.
The output structure likes: https://github.com/cpunion/clibs/blob/main/wasi-sdk/lib.yaml, don't need keep clang and llvm, only sysroot, libclang wasm32 builtin needed, those are cross platform, so you can download one of the prebuilt package of any platform.