Properties with class attributes appear to not work.

[calbot]

I get the following error message...
Build error unknown property attribute 'class'

For this line
@property (class, nonatomic, strong, readonly) DDLog *sharedInstance;

Does WinObjC support class properties?
https://useyourloaf.com/blog/objective-c-class-properties/

[MSFTFox]

WinObjc ships with Clang version 3.7. This predates the availability of class properties.

[DHowett-MSFT]

Fixed with #2869