std: implement `Futex` for WebAssembly

Implements std's `Futex` for the WebAssembly target using Wasm's
`atomics` instruction set. When the `atomics` cpu feature is disabled
we emit a compile-error.
ea0d4c8377Luuk de Gram committed on 6/26/2023, 6:00:57 PMparent062eb6f
1 file changedLine totals unavailable