Use Legacy Swift Language Versio

Use Legacy Swift Language Version” (SWIFT_VERSION)

• 使用cocoapods导入swift框架导致
• 在Podfile最后加上

post_install do |installer|
  installer.pods_project.targets.each do |target|
    target.build_configurations.each do |config|
      config.build_settings['SWIFT_VERSION'] = '3.0'
    end
  end
end

• 详见stackoverflow