In iOS 9 and OS X 10.11 the old GameKit was effectively renamed GameCenter, while
the new GameKit is a sort of umbrella framework like Cocoa. We need to support
backwards deployment, though, so the GameCenter overlay links to GameKit.framework.
(This is essentially the same solution implemented for CoreImage moving out of
QuartzCore in r28449)
rdar://problem/21340738
Swift SVN r30322
-import-underlying-module deliberately avoids autolinking against that module,
since normally it's used when building the Swift half of a single binary.
For the overlays, however, that's not what we want, so add the underlying
framework explicitly.
Swift SVN r29439
Introduce a number of small overlays to bridge the NSError domains for
a number of frameworks into existing imported enums. This batch only
covers cases where there is an existing NS_ENUM describing the codes
for the domain, so we need only extend that enum to provide the
appropriate _BridgedNSError conformance.
This is the bulk of rdar://problem/20536610.
Swift SVN r28585
