The zoneinfo C extension has the "freefunc m_free" function with signature "static void module_free(void)". The signature of freefunc is "void (*freefunc)(void *)". It takes a void * argument, but module_free() does not.

The signature mismatch is not a problem for most C compilers. But Web Assembly is more strict. wasm32-emscripten fails and aborts at runtime:

worker.js onmessage() captured an uncaught exception: RuntimeError: function signature mismatch
Pthread 0x8a1df0 sent an error! undefined:undefined: function signature mismatch

/python-wasm/cpython/builddir/node/python.js:158
   throw ex;
   ^
Error [RuntimeError]: function signature mismatch
    at module_dealloc (<anonymous>:wasm-function[1883]:0x9a15e)
    at _Py_Dealloc (<anonymous>:wasm-function[1959]:0x9eabe)
    at insertdict (<anonymous>:wasm-function[1624]:0x87ccb)
    at _PyDict_SetItem_Take2 (<anonymous>:wasm-function[1622]:0x8749c)
    at dict_ass_sub (<anonymous>:wasm-function[1708]:0x8e604)
    at PyObject_SetItem (<anonymous>:wasm-function[486]:0x34221)
    at finalize_modules (<anonymous>:wasm-function[3644]:0x1703d0)
    at Py_FinalizeEx (<anonymous>:wasm-function[3641]:0x16f986)
    at Py_RunMain (<anonymous>:wasm-function[4055]:0x191124)
    at pymain_main (<anonymous>:wasm-function[4058]:0x19174d)
Emitted 'error' event on process instance at:
    at emitUnhandledRejectionOrErr (internal/event_target.js:579:11)
    at MessagePort.[nodejs.internal.kHybridDispatch] (internal/event_target.js:403:9)
    at MessagePort.exports.emitMessage (internal/per_context/messageport.js:18:26)