CI support, following the same tiers as rust (https://doc.rust-lang.org/nightly/rustc/platform-support.html).

Tier 1

Tests must pass.

• Linux: tested.
• Windows: tested.
• macOS: tested.

Tier 2

Must build.

• Android: check only.
• FreeBSD: check only.
• Fuchsia: check only.
• NetBSD: check only.
• Redox: check using Rust nightly only, stable is tracked here: Fix building on Redox on Rust stable #181.
• Solaris: check only.
• iOS: check only.
• illumos: check only.

Tier 3

Best effort.

• Haiku
• Hermit
• OpenBSD
• VxWorks
• DragonFly BSD

Old description:

Currently only Linux, macOS and Windows are tested on the CI but we support (to some degree) many more OSes. We should add more of these OSes to the CI, at least running cargo check. For (Rust) tier 1 architecture/OS combos this should be easy, but for other tiers rustup might not be supported.