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• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/tools/notes/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
• You have signed the CLA.
• All existing tests are passing: https://github.com/NativeScript/nativescript-cli/blob/master/CONTRIBUTING.md#contribute-to-the-code-base
• Tests for the changes are included.

What is the current behavior?

Right now, developers are forced to include iOS native source code via plugins (Obj-C, Swift) or within single project location: App_Resources/iOS/src.

There's also an option to create a local Swift Package to house shared native source code to be consumed by the project (via the current SPMPackages option of config: https://docs.nativescript.org/configuration/nativescript#ios-spmpackages). This can be a fine option in some cases however comes with some overhead in that Swift Packages have member access considerations (meaning generally would need to have proper public access modifiers including proper public initializers for accessing from the swift package).

What is the new behavior?

This allows a long desired ability to include native source code from anywhere in the project including outside the project directory given workspace setups. For example, developers can now configure nativescript.config as follows:

• Including any .swift files anywhere within project/src directory:

ios: {
    NativeSource: [
      {
        name: 'ProjectPlatformSrc',
        path: './src/**/*.swift'
      }
    ],

This will create a file reference folder named ProjectPlatformSrc within the generated Xcode project containing any .swift files found anywhere within the projects src directory.

• Including any .swift files anywhere within project/src directory, including any (Swift, Obj-c impl/headers, as well as any module.modulemap files) within workspace packages or libs dir:

ios: {
    NativeSource: [
      {
        name: 'ProjectPlatformSrc',
        path: './src/**/*.swift'
      },
      {
        name: 'Auth',
        path: '../../packages/**/*.{swift,m,h,modulemap}'
      },
      {
        name: 'Purchasing',
        path: '../../libs/**/*.{swift,m,h,modulemap}'
      }
    ],

Doc added: NativeScript/docs#161