There is an updated pull request by q66 against master on the void-packages repository

https://github.com/void-ppc/void-packages rust140
https://github.com/void-linux/void-packages/pull/17684

Rust 1.40
Testing:

- [x] x86_64
- [x] x86_64-musl
- [x] ppc*
- [x] aarch64(-musl)
- [x] armv7l(-musl)
- [x] Firefox builds

Depends on https://github.com/void-linux/void-packages/pull/17671

A patch file from https://github.com/void-linux/void-packages/pull/17684.patch is attached