rust: types: add FOREIGN_ALIGN to ForeignOwnable

The current implementation of `ForeignOwnable` is leaking the type of the
opaque pointer to consumers of the API. This allows consumers of the opaque
pointer to rely on the information that can be extracted from the pointer
type.

To prevent this, change the API to the version suggested by Maira
Canal (link below): Remove `ForeignOwnable::PointedTo` in favor of a
constant, which specifies the alignment of the pointers returned by
`into_foreign`.

With this change, `ArcInner` no longer needs `pub` visibility, so change it
to private.

Suggested-by: Alice Ryhl <[email protected]>
Suggested-by: Maíra Canal <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Acked-by: Danilo Krummrich <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Signed-off-by: Andreas Hindborg <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

0 files changed, 0 insertions, 0 deletions