Debian packaging of emscripten provides executables in $PATH. Please try use those.
It's not me who is trying to use the executables from /usr/share/emscripten, it's emscripten itself. Notably, emcmake requires it in /usr/share/emscripten/cmake/Modules/Platform/Emscripten.cmake, which is where I initially encountered the error, but the entire codebase of emscripten expects the executables to be present in EMSCRIPTEN_ROOT, which is /usr/share/emscripten/ in debian.
emscripten 2.0.12~dfsg-2 depends on node-acorn, so the cause for above error must be a different one.
Well, you can try it yourself. The require in /usr/share/emscripten/tools/acorn-optimizer.js fails unless acorn is manually installed to /usr/share/emscripten/node_modules.
