Disable problematic jobs that involve Github Actions caching or `cross`
whenever the environment is set to ACT. This allows running the CI
pipeline locally and hopefully speeds up PR cycle times by reducing
unexpected CI pipeline results.
Based on the original work by Justin Moon.
*MSRV unchanged from 1.29.0.*
When `std` is off, `no-std` must be on, and we use the [`alloc`](https://doc.rust-lang.org/alloc/) and core2 crates. The `alloc` crate requires the user define a global allocator.
* Import from `core` and `alloc` instead of `std`
* `alloc` only used if `no-std` is on
* Create `std` feature
* Create `no-std` feature which adds a core2 dependency to polyfill `std::io` features. This is an experimental feature and should be
used with caution.
* CI runs tests `no-std`
* MSRV for `no-std` is 1.51 or so
Andrew Ahlers
Dr Maxim Orlovsky
Riccardo Casatta
Martin Habovstiak
Devrandom
Andrew Poelstra
Sebastian Geisler