Macro `is_mips64_feature_detected`

macro_rules! is_mips64_feature_detected {
    ("msa") => { ... };
    ($t:tt,) => { ... };
    ($t:tt) => { ... };
}

Check for the presence of a CPU feature at runtime.

When the feature is known to be enabled at compile time (e.g. via -Ctarget-feature) the macro expands to true.