Summary:
Introduced a helper macro `rn_codegen_cli()` that defines ":write_to_json" and ":rn_codegen" targets differently based on the environment. When run at FB, it uses FB-specific setup. When run in OSS as a standalone repo, we use `yarn install` and `yarn run build` directly, then use `node` to run the output CLI.
This way, the same target can be used in both environments on other Buck targets.
Motivation: we need this to define rn_codegen_modules() to use codegen to produce Java TurboModule specs, that can be built by CircleCI (we build ReactAndroid via Buck as well). That way we can finally removed the checked-in .java spec files.
Changelog: [Internal]
Reviewed By: hramos
Differential Revision: D24442468
fbshipit-source-id: b1e5fce275100cfe3a1b3ae6d61c1c6d4b25651b
Kevin Gozali