Function derive_unaligned_struct 

pub(crate) fn derive_unaligned_struct(
    ast: &DeriveInput,
    strct: &DataStruct,
    zerocopy_crate: &Path,
) -> Result<TokenStream, Error>

A struct is Unaligned if:

• repr(align) is no more than 1 and either
  • repr(C) or repr(transparent) and
    • all fields Unaligned
  • repr(packed)