-#define yaffs_strcat(a,b) strcat(a,b)
-#define yaffs_strcpy(a,b) strcpy(a,b)
-#define yaffs_strncpy(a,b,c) strncpy(a,b,c)
-#define yaffs_strnlen(s,m) strnlen(s,m)
+#ifndef Y_LOFF_T
+#define Y_LOFF_T loff_t
+#endif
+
+/* Some RTOSs (eg. VxWorks) need strnlen. */
+size_t strnlen(const char *s, size_t maxlen);
+
+#define yaffs_strcat(a, b) strcat(a, b)
+#define yaffs_strcpy(a, b) strcpy(a, b)
+#define yaffs_strncpy(a, b, c) strncpy(a, b, c)
+#define yaffs_strnlen(s, m) strnlen(s, m)