[Feature] Exclude supports for certain platform

[Sunbreak]

https://pub.dev/packages/libusb supports only Windows/macOS/Linux

Could we exclude the TAGs of Android/iOS?

BTW: libusb is a Dart package, neither Flutter plugin nor Flutter package. None of it dependency declared something like:

flutter:
  plugin:
    platforms:
      android: xxx
      ios: xxx

[isoos]

@Sunbreak: can you think of any intrinsic property inside the package that we can detect and could suggest us that it supports desktop platforms only?

[Sunbreak]

Maybe something like:

dart:
  native:
    platforms: [windows, linux, macos]

[isoos]

@Sunbreak: I was thinking if there is in the code, the dependencies, in the layout of the project or in the content of the files that necessarily excludes mobile platforms. We tend to prefer inferring these as opposed to requiring to specify explicitly.

[Sunbreak]

libusb is quite basical. It only depends on the libusb-1.0.dll/dylib/so

I don't think it could be inferred from the code, the dependencies or the layout of the project. pubspec.yaml is the only thing comes up with

[stuartmorgan-g]

In general, there's unlikely to be a way to detect platform limitation of a package whose limitation comes from either FFI or Process calls.

[sigurdm]

This has been fixed in pana already, and will show up in a coming pub release.

Closing as a duplicate of dart-lang/pana#889