swift234

Clang importer: allow the swift_name attribute to map any name.

This is functional for arbitrary Objective-C properties and methods
(the subject of rdar://problem/22214302), as well as for changing the
argument labels of C functions. However, it does not work when the
name of a global is changed because name lookup initiated from
Swift goes through the Swift lookup table. Fixes
rdar://problem/22214302 but is only a step toward
rdar://problem/17184411.

Swift SVN r32670