Duplicate symbols when linking Android on Rust 1.60

[YuhanLiin]

When building multiple crates that export Android APIs via flapigen, the final linking step fails with the error: ld error: duplicate symbol: JNI_OnLoad. This only happens on Rust 1.60 and not older versions. This is caused because of rust-lang/rust#83822, which removes support for duplicate symbols on Android targets.

[Dushistov]

Not sure that going to fix this. This project is designed to work with the idea that only top level crate uses flapigen.
Not the many crate provides C API and somehow combined into big library, the idea that all crates provide Rust API,
and only top level crate provides C API.