[VS Code] enable define in C & C++

Setting Visual Studio Code

c_cpp_properties.json
ctrl+shift+p
>C/C++:Edit Configuration (JSON)

Make c_cpp_properties.json in .vscode folder, and
 - Updated c_cpp_properties.json syntax

"configurations": [
    {
        "defines": [
            "WIN32",
        ],
        // ...
    }
],