CMake target processor error in MSVC 2017

Just checked out ChakraCore and attempted to build using MSVC 2017 per the directions in README:

> * Clone ChakraCore through git clone https://github.com/Microsoft/ChakraCore.git
> * Open Build\Chakra.Core.sln in Visual Studio
> * Build Solution

It seemed to build successfully:
```
========== Build: 29 succeeded, 0 failed, 0 up-to-date, 2 skipped ==========
```

However this error appeared in the Error List window:
> Error CMake Error at D:\src\ChakraCore\CMakeLists.txt:47 (message):
> Couldn't detect target processor, try `--arch` argument with build.sh

Not sure if I can safely ignore that or not.