Macro features

macro_rules! features {
    (
      @TARGET: $target:ident;
      @CFG: $cfg:meta;
      @MACRO_NAME: $macro_name:ident;
      @MACRO_ATTRS: $(#[$macro_attrs:meta])*
      $(@BIND_FEATURE_NAME: $bind_feature:tt; $feature_impl:tt; $(#[$deprecate_attr:meta];)?)*
      $(@NO_RUNTIME_DETECTION: $nort_feature:tt; )*
      $(@FEATURE: #[$stability_attr:meta] $feature:ident: $feature_lit:tt;
          $(without cfg check: $feature_cfg_check:tt;)?
          $(implied by target_features: [$($target_feature_lit:tt),*];)?
          $(#[$feature_comment:meta])*)*
    ) => { ... };
}

🔬This is a nightly-only experimental API. (stdarch_internal)