The build on Xcode 6.3 seems to have been broken by 1fb3273cfd5bb1b0d334e2b0eefdcf6cfbdd22e3. It changes the version of clang from Xcode 6.3 to 3.6 but I don't think that's correct. It still reports that it's based on 3.6svn.
|For Gerrit Dashboard: QTBUG-46833|
|115201,2||Apple's 3.6.0svn based clang doesn't support -Winconsistent-missing-override||5.5||qt/qtbase||Status: MERGED||-1||0|