arm64 Android build target failing

[fluffyemily]

Running cargo build -p mentat_ffi --target aarch64-linux-android --release returns an error

Compiling tokio-threadpool v0.1.4
error[E0308]: mismatched types
   --> /Users/emilytoop/.cargo/registry/src/6github.com-1ecc6299db9ec823/mio-0.6.14/src/sys/unix/uds.rs:144:33
    |
144 |                                 len_i32))?;
    |                                 ^^^^^^^ expected u32, found i32

'+fp' is not a recognized feature for this target (ignoring feature)
'+fp' is not a recognized feature for this target (ignoring feature)
   Compiling mentat v0.7.0 (file:///Users/emilytoop/Development/mentat)
error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.
error: Could not compile `mio`.
warning: build failed, waiting for other jobs to finish...
error: build failed

It looks like a dependecy we have does not support arm64