我找到一个解决办法，把代码放在你的podfile的末尾

dynamic_frameworks = ['AFNetworking', 'OtherLibToBecomeFramework']
pre_install do |installer|
  installer.pod_targets.each do |pod|
    if dynamic_frameworks.include?(pod.name)
      puts "Overriding the build_type to dynamic_framework for #{pod.name}"
      def pod.build_type;
        Pod::BuildType.dynamic_framework
      end
    end
  end
end

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