Cores not exporting as ES6 Module when compiled with Emscripten to WebAssembly

Where do you define options for Emscripten such as -s EXPORT_ES6=1 and -s MODULARIZE=1 for the final WASM/JS output of dist-cores.sh? I've defined them here: https://github.com/libretro/RetroArch/blob/master/Makefile.emscripten#L9

But the final output JS still does not export ES6 modules, causing you to use very legacy style 1990's style script tags instead of module loading, not properly supporting async, and I get these compiler warnings during linking:

CC gfx/video_filters/phosphor2x.c
emcc: warning: linker setting ignored during compilation: 'EXPORTED_FUNCTIONS' [-Wunused-command-line-argument]
emcc: warning: linker setting ignored during compilation: 'ALLOW_MEMORY_GROWTH' [-Wunused-command-line-argument]
emcc: warning: linker setting ignored during compilation: 'EXPORTED_RUNTIME_METHODS' [-Wunused-command-line-argument]     
emcc: warning: linker setting ignored during compilation: 'EXPORT_ES6' [-Wunused-command-line-argument]
emcc: warning: linker setting ignored during compilation: 'MODULARIZE' [-Wunused-command-line-argument]

Flag here: https://github.com/emscripten-core/emscripten/blob/main/src/settings.js#L1176

Start with dist-cores.sh and Makefile.emscripten, then trace where the final Emscripten link command is assembled. Review the reported linker warnings and verify how EXPORT_ES6 and MODULARIZE reach the final WASM/JS output. Done means the generated JavaScript exports as an ES6 module and the warnings no longer occur during linking.