Update the build script to generate XCFrameworks
Update the build script to generate XCFrameworks

This currently only generates XCFrameworks for iOS. Note that XCFramework can contain
slices for all platforms. Currently, tvOS scripts are not generating all the necessary
slices for simulator, so it needs to be updated.

jasonacox/Build-OpenSSL-cURL,jasonacox/Build-OpenSSL-cURL