Macro target_features 

macro_rules! target_features {
    ($($feature:tt),* $(,)?) => { ... };
}

Constructs a TargetFeatures value from target feature names.

Each name identifies a target feature. Multiple names are combined using TargetFeatures::with.

const REQUIRED: target_features::TargetFeatures =
    target_features::target_features!("avx", "fma", "bmi2");