Enable some android host builder

[malbarbo]

There are some interest in running rust in android devices, see for example: termux/termux-packages#261, https://www.reddit.com/r/rust/comments/631bl2/exciting_rust_coming_to_android_and_chromebooks/

We have disabled android builders, it would be great if we enabled some of these builders, so users of android devices (including chromebooks) would be able to run rustc.

As discussed here, we are running at the limit of our travis capacity, so it must be discussed.

[Mark-Simulacrum]

Nominating. We have some capacity now, perhaps one of these can be enabled (and possibly in place of the existing arm-android builder?)

[jasondavies]

See also this recent blog post: “My $169 development Chromebook” about using Chrome OS and Termux. It would be nice if rustup worked on Termux.

[brinsche]

There's already an issue about that: termux/termux-packages#261

I think the binaries are the only thing missing, rustup.rs already provides binaries for installing rustup on android.

I would vote for aarch64-linux-android as the first builder

[aturon]

cc @rust-lang/infra

[aidanhs]

We've discussed this in the infra team meeting - unfortunately this requires another builder, and therefore someone willing to fund that builder. Even with that, the process for accepting money is still being ironed out by the core team. So the answer is unfortunately "not yet".

[phil-opp]

I think it's worth revisiting this issue given that the CI situation has considerably changed. AFAIK, Microsoft now sponsors the CI builders, so maybe it is possible to add this additional builder now?

[Friz64]

I would really like to use rustup with Termux (nightly and so on), please make this happen

[programmerjake]

Can this be re-nominated for discussion? I'd expect a lot has changed in the past 4 years, having rustup work on aarch64-linux-android would be awesome!

[jack2f]

install scrapy in termux with command
pip install scrapy
meet error message below:
`This package requires Rust >=1.41.0.
[end of output]

note: This error originates from a subprocess, and is likely not a problem with pip.
ERROR: Failed building wheel for cryptography
Successfully built lxml
Failed to build cryptography
ERROR: Could not build wheels for cryptography, which is required to install pyproject.toml-based projects`
how to do then?