A 'lazy' compilation mode to make writting multiplatform code easier without having to clutter the project

[Richard (Rikki) Andrew Cattermole]

Why wouldn't this work?

```d
else version(WASM) {
	void poll() {
		pragma(inline, true);
		// or assert(0);
		// or noreturn ext.
	}
} else static assert(0);
```