pub fn current() -> Result<Self, Error> {
        let triple = Triple::new(CURRENT_TARGET).map_err(Error::UnknownPlatformTriple)?;
        let target_features = TargetFeatures::features(CURRENT_TARGET_FEATURES.iter().copied());
        Ok(Self {
            triple,
            target_features,
            flags: BTreeSet::new(),
        })
    }
Returns the current platform, as detected at build time.

This will return an error if the current platform was unknown to this version of
`target-spec`.
target-spec/src/platform.rs