Defining the variables at the beginning of the function forces the types
to be default constructible, which may not be desirable; furthermore, it
also forces the move/copy assignment operator to be used when the
deserialized value is retrieved.
Having `T val = f()` has the advantage of benefitting from potential RVO
as well as not requiring `T` to be default constructible, so generate
code in that form by calling `deserialize_call()` with `declare=true`.
Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>