I have a third party project in my Xcode workspace (it\'s a dependency for my main project) and I want Xcode to ignore all build warnings from that third party project.
It is possible on a per file basis, see the blog entry at http://blog.bluelightninglabs.com/2011/12/suppressing-xcode-warnings-on-a-per-file-basis/
To summarize: Use the compiler flags on the “Build phases” tab.