This is needed if we compile StdlibUnittest with -sil-serialize-all
So far I added the imports only in files which needed them. But this may change, depending on the optimizer (inlining).
Adding them in all files doesn't harm and avoids confusion if someone makes an unrelated change which would result in such a linker error.
Some of the tests had bitrotted, and others no longer worked
because they used frameworks such as CoreAudio that are not
available in the public SDK for watchOS.
Swift SVN r32733
Enable checking for uses of potentially unavailable APIs. There is
a frontend option to disable it: -disable-availability-checking.
This commit updates the SDK overlays with @availability() annotations for the
declarations where the overlay refers to potentially unavailable APIs. It also changes
several tests that refer to potentially unavailable APIs to use either #available()
or @availability annotations.
Swift SVN r27272
