Resolve warning: enumeration value ‘FILE_SORT_NATURAL’ not handled in switch

src/sbbs3/filedat.c

@@ -358,6 +358,8 @@ void sortfiles(file_t* filelist, size_t count, enum file_sort order)
 		case FILE_SORT_SIZE_D:
 			qsort(filelist, count, sizeof(*filelist), file_compare_size_d);
 			break;
+		case FILE_SORT_NATURAL:
+			break;
 	}
 }