pyodide: RuntimeError: Incorrect Emscripten version 3.1.27. Need Emscripten version 3.1.32

🐛 Bug

I’m building pylibjpeg-openjpeg to allow pydicom (pure Python works in Pyodide already) to read Jpeg2000 encoded DICOM images.

To Reproduce

mkdir pyodide_builds
cd pyodide_builds
pyenv local 3.11.2
python -m venv venv
source venv/bin/activate
python -m pip install pyodide-build
git clone https://github.com/emscripten-core/emsdk.git
cd emsdk
PYODIDE_EMSCRIPTEN_VERSION=$(pyodide config get emscripten_version)
./emsdk install ${PYODIDE_EMSCRIPTEN_VERSION}
./emsdk activate ${PYODIDE_EMSCRIPTEN_VERSION}
source emsdk_env.sh
cd ..
git clone --recurse-submodules https://github.com/pydicom/pylibjpeg-openjpeg
cd pylibjpeg-openjpeg
pyodide build

This works perfectly and builds a wheel (pylibjpeg_openjpeg-1.3.2-cp311-cp311-emscripten_3_1_32_wasm32.whl). However it won’t load in JupyterLite or Pyscript because they all use Emscripten 3.2.27. They error with:

ValueError: Wheel was built with Emscripten v3.1.32 but Pyodide was built with Emscripten v3.1.27

So I attempted to change the build instructions to use PYODIDE_EMSCRIPTEN_VERSION=3.1.27 instead of PYODIDE_EMSCRIPTEN_VERSION=$(pyodide config get emscripten_version) but I attempt to run pyodide build this fails with:

RuntimeError: Incorrect Emscripten version 3.1.27. Need Emscripten version 3.1.32

So how can I build pyodide packages with older versions of Emscripten?

Thanks