How do I disable warnings for a static framework in Xcode?

I'd like to build my Xcode project with `-Weverything`. Unfortunately my project uses the opencv2.framework (built as a static framework for iOS), and the header files for that framework are not `-Weverything` clean.

When using clang from the command line, I can use the `-isystem` flag to specify system header files that should be ignored for compiler warnings. Is there a similar feature for frameworks? And if so, how do access it from Xcode?

As for me most of warnings occurred by documentation comments. So I go Project -> Build Settings and set Documentation Comments value to No. It hides all warnings also from static frameworks.