fix workaround for PDFBorder crasher, on 10.13 it now uses NSInteger for the count
fix workaround for PDFBorder crasher, on 10.13 it now uses NSInteger for the count

JackieXie168/skim,JackieXie168/skim,JackieXie168/skim,JackieXie168/skim,JackieXie168/skim