WASM4 and D for retro game programming

[Shigeki Karita]

I recently found that [WASM4](https://wasm4.org/) officially 
supports D language to build retro games like [Game 
Boy](https://en.wikipedia.org/wiki/Game_Boy) for web browser and 
native apps.

https://wasm4.org/docs/getting-started/setup

These are my small examples written in D:

- 
https://github.com/christopher-kleine/wasm-4-tutorial-games/tree/main/snake-d
- https://github.com/ShigekiKarita/wasm4-puyo (hosted at 
https://karita.xyz/wasm4-puyo)
- https://github.com/ShigekiKarita/wasm4-flappy-bird (hosted at 
https://karita.xyz/wasm4-flappy-bird)

I think it is very fun experience with D's betterC mode. Let's 
join this upcoming game jam
https://itch.io/jam/wasm4
https://www.youtube.com/watch?v=hWGu4SqlRy0