Fix to crash in iOS 11 if binary built with base SDK iOS 10
Fix to crash in iOS 11 if binary built with base SDK iOS 10

Fixes https://github.com/kishikawakatsumi/SpreadsheetView/issues/137

kishikawakatsumi/SpreadsheetView,kishikawakatsumi/SpreadsheetView,kishikawakatsumi/SpreadsheetView,kishikawakatsumi/SpreadsheetView