Fixed the build error in App veyor
Fixed the build error in App veyor

nazim9214/NLog,bryjamus/NLog,snakefoot/NLog,UgurAldanmaz/NLog,hubo0831/NLog,NLog/NLog,bhaeussermann/NLog,AndreGleichner/NLog,tetrodoxin/NLog,304NotModified/NLog,breyed/NLog,MartinTherriault/NLog,nazim9214/NLog,breyed/NLog,bhaeussermann/NLog,michaeljbaird/NLog,MoaidHathot/NLog,MoaidHathot/NLog,michaeljbaird/NLog,littlesmilelove/NLog,ie-zero/NLog,littlesmilelove/NLog,hubo0831/NLog,tetrodoxin/NLog,tohosnet/NLog,AndreGleichner/NLog,BrutalCode/NLog,kevindaub/NLog,UgurAldanmaz/NLog,MartinTherriault/NLog,ilya-g/NLog,luigiberrettini/NLog,bjornbouetsmith/NLog,BrutalCode/NLog,kevindaub/NLog,bryjamus/NLog,sean-gilliam/NLog,ilya-g/NLog,ie-zero/NLog,luigiberrettini/NLog,tohosnet/NLog,bjornbouetsmith/NLog