Why so many warnings in xcode?

Like the picture. I just create a new project and not added any thing in my project. Just set iOS player setting and build to xcode project.

Whan I put the"Build and Run",it can build and run in my ipad. But it appears a lot of warnings in the xcode!

Have anybody can tell me why?and how to fix?

(P.S. I use Unity 3.3 + iOS 4.3 + iPad)