swift234

Map Clang's 'deprecated' attribute to @availability(*, deprecated).

Previously, we were importing Clang's 'deprecated' attribute in as
@availability(*, unavailable), based on the idea things that were
unconditionally deprecated in Objective-C shouldn't even be accessible
in Swift. (We were motivated by 'tmpnam', among others). However, this
plays havoc with mixed Objective-C/Swift projects, because the
Objective-C 'deprecated' attribute was useless as a mechanism for
making internal changes in the project. We have Clang's
__attribute__((availability(swift, unavailable))) to make an API
unavailable in Swift, so the deprecated -> unavailable mapping here no
longer makes sense.

Fixes rdar://problem/18934173.

Swift SVN r27358