ECL for target `wasm32-unknown-emscripten` on host `arm64-apple-darwin`

Greetings!

Has anyone managed to build ECL for target wasm32-unknown-emscripten on host arm64-apple-darwin?

The note in INSTALL says we need to build a 32 bit version of the host, but apparently 32 bits arch isn't supported.

Why must ecl be build with -m32? Can't I just use my native ECL arm64-apple-darwin?

Any hint would be appreciated

Thanks