From: Benno Lossin <y86-dev@xxxxxxxxxxxxxx>
Add helper functions to more easily initialize `Opaque<T>` via FFI and
rust raw initializer functions.
These functions take a function pointer to the FFI/raw initialization
function and take between 0-4 other arguments. It then returns an
initializer that uses the FFI/raw initialization function along with the
given arguments to initialize an `Opaque<T>`.
Signed-off-by: Benno Lossin <y86-dev@xxxxxxxxxxxxxx>