[Windows] Errors when compiling Skia using MSVC and Ninja

[Aitor Gomila]

I am using MSVC and Ninja to build a project that requires Skia.

```

cmake -GNinja -DCMAKE_C_COMPILER=cl -DCMAKE_CXX_COMPILER=cl -DCMAKE_LINKER=link
```

I am getting what seem multiple Skia coding errors even though I didn't change a LOC from skia.

The skia fork is a bit old, but it works rightaway in Linux. Maybe I should use VS's generator instead of Ninja?

Full output: https://pastebin.com/LhhzGVKw