[swift-evolution] [Draft] Target-specific CChar

[Ben Rimmington]

Apart from `CChar`, are the other typealiases in "CTypes.swift" also not portable?

For example, `CLong` and `CUnsignedLong` with LLP64 platforms (e.g. Microsoft Windows)?

Should the Clang Importer use the same typealiases in generated interfaces, to encourage portability?

> - public func labs(_: Int) -> Int
> + public func labs(_: CLong) -> CLong

-- Ben