Macro arch_map_data 

macro_rules! arch_map_data {
    () => { ... };
    (
        BidiTryFrom < $type_name1:ty, $type_name2:ident > { $($field1:ident =
        $field2:ident;)* $(.. $d:expr)? } $($token:tt)*
    ) => { ... };
}

Implement TryFrom between 2 uapi struct of different ABI with a common type.