Tests in this directory are for functionality that has changed in GCC
from one release to another or that is not ABI-compliant and may change
in a future release.

Each test header for changed behavior should indicate the version in
which the behavior changed, in order to help users of these tests to
determine whether a test failure is expected or not.

Every test in this directory that covers behavior that is not
ABI-compliant should also be covered by a test for -Wabi to ensure that
there is a warning for the construct.