matchMedia not a function

[Mintyboi]

In #18826, glfw was updated to 3.3 as well as including changes for scaling dpi.
However, these changes does not seem to be compatible with the proxy options in emscripten (PROXY_TO_WORKER and PROXY_TO_PTHREAD).

Reason being, when using the proxy flags, the javascript file will be loaded in a web worker and APIs like window.matchMedia and window.devicePixelRatio are not available in web workers.

Reproducer in CI: #19911

[Mintyboi]

Tagging @coderedart who is the author of #18826

[coderedart]

What would the alternative be?

[kripken]

The general solution for this is to proxy those calls to the main thread. Here is an example of how to annotate a function to be proxied:

emscripten/src/library_sdl.js

Lines 1606 to 1607 in 985c489

	SDL_UnlockSurface__proxy: 'sync',
	SDL_UnlockSurface: function(surf) {

A PR to add those annotations for the relevant functions would be great.