use lstat when checking whether file is a symlink

cmd/backup/main.go

@@ -518,15 +518,16 @@ func (s *script) pruneOldBackups() error {
 
 		var candidates []string
 		for _, candidate := range globMatches {
-			fi, err := os.Stat(candidate)
+			fi, err := os.Lstat(candidate)
 			if err != nil {
 				return fmt.Errorf(
-					"pruneOldBackups: error calling stat on file %s: %w",
+					"pruneOldBackups: error calling Lstat on file %s: %w",
 					candidate,
 					err,
 				)
 			}
-			if fi.Mode() != os.ModeSymlink {
+
+			if fi.Mode()&os.ModeSymlink != os.ModeSymlink {
 				candidates = append(candidates, candidate)
 			}
 		}