Include Native FS as an additional file system

[erdalkaraca]

The pyodide project managed to allow mounting the file system access API as a FS backend:

https://github.com/pyodide/pyodide/blob/eae76c367abdf42953065bfec86c66c3d4b82b2c/src/js/api.ts#L545

It would be great to include the native file system in addition to the other supported file systems (MEMFS, IDBFS, NODEFS).

[erdalkaraca]

Just had a brief look at pyodide's native FS: I think this request is out of reach as emscripten itself does not support the file system access API which was my assumption. Pyodide uses the MEMFS as a temp file system, then syncs between MEMFS and their own native FS implementation.