It keeps saying:
fatal error: file \'/Applications/Xcode5-DP5.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk/usr/includ
In addition to all of the other "clean your build" answers, nothing was working for me until I emptied out the (highly undocumented!) /var/folders
directory.
Apparently, this is a "miscellaneous caches" dir maintained by OS-X. I didn't even bother figuring out what were "the correct files"; I just cleaned out the entire directory.
...And now I can build again. Hooray! From terminal:
[sudo] rm -rf /var/folders/*
(Although I did it from Finder, via authentication.) (OS-X 10.9.latest)
Additional clue: I could build with XCode-6-beta, but got the goofy corrupt error in XCode-5.