Fix use S_IFTM to check file type
Fix use S_IFTM to check file type

As seen in `man 2 stat`, S_IFTM is needed to check the filetype

Issue #184

der-lyse/newsboat,der-lyse/newsboat,newsboat/newsboat,newsboat/newsboat,newsboat/newsboat,newsboat/newsboat,newsboat/newsboat,der-lyse/newsboat,newsboat/newsboat,der-lyse/newsboat,newsboat/newsboat,der-lyse/newsboat,der-lyse/newsboat,der-lyse/newsboat,der-lyse/newsboat,newsboat/newsboat