Anyone who is using XCode7 and getting linker warnings like this: [all for iOS, but I suspect OS X will see similar]
Object file (.......fupaotdixhkghddnqyzikcenrcwf/Build/Products/Debug-iphonesimulator/libcocos2d.a(OALSimpleAudio.o)) was built for newer iOS version (9.0) than being linked (8.2)
The culprit is the minimum deployment target for the ObjectAL library - In Xcode delve into the cocos2d project -> external -> ObjectAL project: Goto build settings and search for 'deployment target' and set the value to be <= your main project minimum deployment target.
Rebuild and the (26 for me) warnings go away.
There are a few other XCode7 warnings - usual 'update to latest project settings' and two real ones - CCAppDelegate.m: supportedInterfaceOrientations return type has (sortof) changed - the new type 'UIInterfaceOrientationMask' it wants is still an NSUInteger, just a more well defined enum. Second one is the same issue.