macro_rules! platform {
{ unix => $unix:expr, windows => $windows:expr $(,)? } => {
if cfg!(unix) {
#[cfg(unix)] { $unix }
#[cfg(not(unix))] { unreachable!() }
} else if cfg!(windows) {
#[cfg(windows)] { $windows }
#[cfg(not(windows))] { unreachable!() }
} else {
#[cfg(not(any(unix, windows)))] compile_error!("Unsupported platform");
unreachable!()
}
}
}