My code uses the following types on the FFI:

struct Foo(NonZeroU64);
struct Bar {
  foo: Option<Foo>,
}

What I want here really is foo: u64.

What cbindgen ends up producing is:

typedef struct Option_Foo Option_Foo;

It looks like this opaque type leaves me no way to redefine the binding in the header, or work around otherwise. Is there anything we could to do make this work?