Using the Windows headers with Unicode

[Straivers via Digitalmars-d-learn]

So I've been trying to create a window, and have been working my 
way through the MSDN tutorials. However, I have always had to 
specifically specify if I was using either the Unicode or ANSI 
version of a struct or function. Looking through the druntime 
code (especially winuser.d), it appears that one should be able 
to simply set a Unicode version identifier when compiling, be it 
with dub or without. I've included the relevant portion of my 
.dub file below along with the commands I have used. What am I 
doing wrong?

"versions":["Unicode"],
"configurations": [
    {
        "name": "dev",
        "versions":["debugMode", "debugInfo", "unittests"],
    }
],
...
dub --config=dev

Thank you for your time.