swift234

Import MacTypes.Boolean as a dedicated DarwinBoolean type.

Like ObjCBool is a legitimate boolean type rather than a typealias for Int8,
DarwinBoolean is better than a typealias for UInt8. It's a BooleanType
(meaning you can use it directly in if/while/?:) and BooleanLiteralConvertible
(meaning you can use 'true' and 'false').

The next commit goes even further, so that you only have to deal with
DarwinBoolean when ABI is important. At all other times it should be
bridged with Bool, just like ObjCBool.

rdar://problem/19013551

Swift SVN r30050