-#define SORT_FORWARD 0 /* sort in reverse order */
-#define SORT_REVERSE 1 /* sort in reverse order */
-#define SORT_NAME 2 /* sort by file name */
-#define SORT_SIZE 3 /* sort by file size */
-#define SORT_ATIME 4 /* sort by last access time */
-#define SORT_CTIME 5 /* sort by last change time */
-#define SORT_MTIME 6 /* sort by last modification time */
-#define SORT_VERSION 7 /* sort by version */
-#define SORT_EXT 8 /* sort by file name extension */
-#define SORT_DIR 9 /* sort by file or directory */
+static const int SORT_FORWARD = 0; /* sort in reverse order */
+static const int SORT_REVERSE = 1; /* sort in reverse order */
+static const int SORT_NAME = 2; /* sort by file name */
+static const int SORT_SIZE = 3; /* sort by file size */
+static const int SORT_ATIME = 4; /* sort by last access time */
+static const int SORT_CTIME = 5; /* sort by last change time */
+static const int SORT_MTIME = 6; /* sort by last modification time */
+static const int SORT_VERSION = 7; /* sort by version */
+static const int SORT_EXT = 8; /* sort by file name extension */
+static const int SORT_DIR = 9; /* sort by file or directory */