thread 'main' panicked at $DIR/panic-in-ffi.rs:13:5: Test note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace thread 'main' panicked at library/core/src/panicking.rs:$LINE:$COL: panic in a function that cannot unwind stack backtrace: thread caused non-unwinding panic. aborting.