* Need to check availability before use of macros.
* Get rid of PCH and enforce macro definition.
* Remove prefix
* Switch to global warning instead, much better.
* no message
* Go further
* Make the symbols public so that apps actually build
* Move ASAvailability into the umbrella header
* Remove duplicate define
* Put the file back where it was in the list
* Revert "Put the file back where it was in the list"
This reverts commit 6a80c15b5b5efe5ff39812a018114e8bdc1dc0cf.
