TinyGo board abstraction

This is an experiment. It may go stale, or it may change in backwards incompatible ways. Don't rely on it too much for now.

Goals

• Provide a common abstraction for boards supported by TinyGo.
• Provide a simulated board
• Auto-generate all board definitions from a devicetree-like format. Don't write any of the definitions by hand. (See Zephyr OS for example).
• Allow generating a similar board definition from target JSON files for custom boards.
• Make it possible to identify hardware at compile time instead of relying on build tags, as long as this doesn't impact binary size too much.

Non-goals

• Provide access to hardware unique to a particular board. A new interface has to be reasonably common, and has to be supported by at least two different boards.
• Support custom boards from this package. Only boards that are (or were) actually produced should be supported. This includes dev boards, maker boards, electronic badges, etc.

License

BSD 2-clause license, see LICENSE.txt for details.