message: Use `make -j2` instead of `make -j`
  Apparently `-j` completely crashes the GitHub Actions runner (or at
  least makes it hang).
diff: @@ -57,7 +57,7 @@ jobs:
  git -C binaryen pull || git clone https://github.com/WebAssembly/binaryen binaryen
  cd binaryen
  cmake .
  - make -j wasm-opt
  + make -j2 wasm-opt
  # FIXME: Use actions-rs/install@v0.1 again once it can handle wasm-bindgen
  - name: Install wasm-bindgen
  