Item 6 said the builtins archive has to come from wasi-sdk. It does not have to, and what is standing in its place is emscripten's compiler-rt for a different triple — which works, and is worth writing down as a substitution rather than leaving as "wasm32 works".
Description
Languages
OCaml
67.2%
Emacs Lisp
15.2%
C
10.4%
HTML
2.9%
Standard ML
2.8%
Other
1.5%