I hadn’t done any Core Location work before iOS 4 came out. But now I am. And I ran into a very odd EXC_BAD_ACCESS bug when running on an iPod touch that’s running iPhone OS 3.1.3. I pinpointed the problem (actually, I think it was only a problem, because I did a lot of other refactoring to get to this point) was with CLLocationCoordinate2DMake. And I finally realised when looking in the header that it’s new for iOS 4. Which is why it fails under iPhone OS.
My fault for being a CL newbie.
In any case, I figure I should share this with others because my searches were fruitless. Enjoy!
UPDATE: The static inline function described by Cocoanetics was immensely helpful and also helped with the next problem I encountered – distanceFromLocation being introduced.