Windows

[pshka]

I've just tried to `dub build` a 3 year old project on Windows 
with the latest DMD :(
What does the below message mean?
```
Performing "debug" build using ldc2 for x86_64.
derelict-util 2.1.0: target for configuration "library" is up to 
date.
derelict-ft 1.0.2: target for configuration "library" is up to 
date.
cairod 0.0.1-alpha.3+1.10.2: building configuration 
"static-custom-windows"...
C:\Users\pshka\AppData\Local\dub\packages\windows-headers-1.0.3\windows-headers\source\windows\httpext.d(70,15): Error: valid linkage identifiers are `D`, `C`, `C++`, `Objective-C`, `Windows`, `System`
C:\Users\pshka\AppData\Local\dub\packages\windows-headers-1.0.3\windows-headers\source\windows\httpext.d(72,15): Error: valid linkage identifiers are `D`, `C`, `C++`, `Objective-C`, `Windows`, `System`
C:\Users\pshka\AppData\Local\dub\packages\windows-headers-1.0.3\windows-headers\source\windows\httpext.d(73,15): Error: valid linkage identifiers are `D`, `C`, `C++`, `Objective-C`, `Windows`, `System`
C:\Users\pshka\AppData\Local\dub\packages\windows-headers-1.0.3\windows-headers\source\windows\httpext.d(74,15): Error: valid linkage identifiers are `D`, `C`, `C++`, `Objective-C`, `Windows`, `System`
C:\Users\pshka\AppData\Local\dub\packages\windows-headers-1.0.3\windows-headers\source\windows\httpext.d(79,15): Error: valid linkage identifiers are `D`, `C`, `C++`, `Objective-C`, `Windows`, `System`
C:\Users\pshka\AppData\Local\dub\packages\windows-headers-1.0.3\windows-headers\source\windows\httpext.d(110,15): Error: valid linkage identifiers are `D`, `C`, `C++`, `Objective-C`, `Windows`, `System`
C:\Users\pshka\AppData\Local\dub\packages\windows-headers-1.0.3\windows-headers\source\windows\mapi.d(125,15): Error: valid linkage identifiers are `D`, `C`, `C++`, `Objective-C`, `Windows`, `System`
C:\Users\pshka\AppData\Local\dub\packages\windows-headers-1.0.3\windows-headers\source\windows\winnetwk.d(296,15): Error: valid linkage identifiers are `D`, `C`, `C++`, `Objective-C`, `Windows`, `System`
ldc2 failed with exit code 1.
```