nix build .#deltachat-rpc-server-armeabi-v7a-android fails with 1.142.3 release

[link2xt]

Release 1.142.2 succeeded, but with 1.142.3 build failed with:

...
        >   = note: ld: error: undefined symbol: epoll_create1
       >           >>> referenced by deltachat_rpc_server.173f32241333f530-cgu.0
       >           >>>               /build/source/target/armv7-linux-androideabi/release/deps/deltachat_rpc_server-f67d6c06900a390c.deltachat_rpc_server.173f32241333f530-cgu.0.rcgu.o:(tokio::runtime::driver::Driver::new::h204a822bad311a05)
       >           >>> did you mean: epoll_create
       >           >>> defined in: /nix/store/almayr53812j425x7nffpxvq4v57w97n-android-sdk-env/share/android-sdk/ndk/24.0.8215888/toolchains/llvm/prebuilt/linux-x86_64/bin/../sysroot/usr/lib/arm-linux-androideabi/19/libc.so
       >           clang-14: error: linker command failed with exit code 1 (use -v to see invocation)
       >           
       >
       >
       > error: aborting due to 1 previous error
       >
       >
       > [naersk] cargo returned with exit code 101, exiting
       For full logs, run 'nix log /nix/store/dl8s1hmi5zfn8wbbswdspf0k3gfay0kv-deltachat-1.142.3.drv'.

This is probably related to this tokio and mio update: 09d4694

As it is one of the architectures we build Android releases for, maybe we need to downgrade it back.

I fixed this issue in mio before, strange that it got broken again: tokio-rs/mio#1590

[link2xt]

Ok, this got broken in tokio-rs/mio#1741

[link2xt]

I would also be fine to just use poll backend https://github.com/tokio-rs/mio/blob/4a5114e518b982f49ce093be6d0d2a2ab86472d1/src/sys/unix/selector/poll.rs for Android, but it is not possible to decide at the compilation time.

[link2xt]

I also wrote an issue in the tokio repo: tokio-rs/tokio#6748

[link2xt]

I guess for now we have to downgrade Tokio: #5856

[link2xt]

This is worked around for now by downgrading to Tokio 1.38. This solution will survive until dependencies start pushing us to upgrade tokio or until some tokio dependency get a RUSTSEC advisory and cargo-deny starts to fail.