Flutter 创建项目后，Xcode编译项目时的几个问题解决。

环境

flutter doctor

[✓] Flutter (Channel stable, 2.0.0, on macOS 11.2.3 20D91 darwin-arm, locale en-CN)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
[✓] Xcode - develop for iOS and macOS
[✓] Chrome - develop for the web
[✓] Android Studio (version 4.1)
[✓] VS Code (version 1.54.1)
[✓] Connected device (2 available)

• No issues found!