How to run Pyxel with the latest Emscripten (3.1.46+)
Hi Pyxel users,

The current web version of Pyxel is built using Emscripten 3.1.45. The reason is that if you compile and run Pyxel with 3.1.46 or later, you will get the following error and audio will not play.

```
Uncaught TypeError: Cannot read properties of null (reading 'apply')
    at dynCall (pyodide.asm.js:9:145551)
    at SDL2.audio.scriptProcessorNode.onaudioprocess (eval at addEmAsm (pyodide.asm.js:9:148345), <anonymous>:1:323)
```

Does anyone have any information on how to solve this problem? I will also provide build instructions if you would like to actually try it. (You will need to modify some parts of build.rs to build Pyxel with the latest version of Emscripten)