+/*
+ * A "directory link" is a link to another git directory.
+ *
+ * The value 0160000 is not normally a valid mode, and
+ * also just happens to be S_IFDIR + S_IFLNK
+ *
+ * NOTE! We *really* shouldn't depend on the S_IFxxx macros
+ * always having the same values everywhere. We should use
+ * our internal git values for these things, and then we can
+ * translate that to the OS-specific value. It just so
+ * happens that everybody shares the same bit representation
+ * in the UNIX world (and apparently wider too..)
+ */
+#define S_IFDIRLNK 0160000
+#define S_ISDIRLNK(m) (((m) & S_IFMT) == S_IFDIRLNK)
+