Emscripten compiles to WASM, which can be loaded via
HTML / JavaScript. This allows you to play OpenTTD inside a
browser.
Co-authored-by: milek7 <me@milek7.pl>
This commit prepares for the next commit, as Emscripten needs to
have a way to trigger a single iteration of the main loop. To
keep the real changes more clear, this commit only unrolls the
loop, and makes no changes to the logic itself.