swift

6c999463 - Add `--preset-vars-file` to `build-script` for easier preset vars handling (#76058)

Add `--preset-vars-file` to `build-script` for easier preset vars handling (#76058) It's not always convenient to pass preset substitution arguments on an interactive command-line. Sometimes one might also need to generate these vars automatically, outside of a `build-script` invocation and also store those vars in a file for later reuse. This change adds a new optional `--preset-vars-file` customization point to `build-script`, which allows users to pass a a file with newline separated key-value pars for preset variables substitution in addition to passing those in a direct `build-script` invocation.