Emscripten settings in configure.ac are not embedding friendly

Bug report

Bug description:

I would like to be able to opt out of certain Emscripten options since I am embedded CPython in a larger application. For example, the forced inclusion of the JS file system is breaking my builds since I use WASMFS in my system which isn't compatible with -lidbfs.js, -lnodefs.js, -lproxyfs.js, -lworkerfs.js. Moreover, I would like to customise the TOTAL_MEMORY option.

Perhaps these options can be on by default but placed behind a flag that can turn them off? For example, --enable-wasm-emscripten-jsfs? Alternatively, perhaps all these settings can be disabled unless one of node, browser, node-debug, browser-debug is set via --with_emscripten_target?

Right now, it seems my only option is to apply a patch to turn these settings off which should be unnecessary in my opinion. @hoodmane @vstinner what do you think?

CPython versions tested on:

CPython main branch

Operating systems tested on:

Other

まず、2340～2351行付近の configure.ac と、既存の --with_emscripten_target の処理を読んでください。現在、Emscripten の JavaScript ファイルシステムオプションと TOTAL_MEMORY がどのように設定されているかを確認し、embedded build でそれらを無効化またはカスタマイズできる方法を定義してください。要求された設定をパッチを維持せずに制御できれば完了です。