Fix compile error for System Fonts
Fix compile error for System Fonts

TukekeSoft/CocosSharp,MSylvia/CocosSharp,mono/CocosSharp,hig-ag/CocosSharp,MSylvia/CocosSharp,mono/CocosSharp,zmaruo/CocosSharp,haithemaraissia/CocosSharp,TukekeSoft/CocosSharp,haithemaraissia/CocosSharp,zmaruo/CocosSharp,hig-ag/CocosSharp