f55dc0824e
This patch uses the Windows APIs to print to the Windows Console, through `llvm::raw_fd_ostream`. This fixes a rendering issue where the characters defined in `DiagnosticsRendering.cpp` (`"╰"` for instance) are not rendered properly on Windows out of the box, because the default codepage is not `utf-8`. This solution is based on [this patch downstream](https://github.com/swiftlang/swift/pull/40632/files#diff-e948e4bd7a601e3ca82d596058ccb39326459a4751470eec4d393adeaf516977R37-R38). rdar://156064500