-/* See fseek(), third argument */
-#define SEEK_CUR _PDCLIB_SEEK_CUR
-#define SEEK_END _PDCLIB_SEEK_END
-#define SEEK_SET _PDCLIB_SEEK_SET
+/* See fseek(), third argument
+ *
+ * Some system headers (e.g. windows) also define the SEEK_* values. Check for
+ * this and validate that they're the same value
+ */
+#if !defined(SEEK_CUR)
+ #define SEEK_CUR _PDCLIB_SEEK_CUR
+#elif SEEK_CUR != _PDCLIB_SEEK_CUR
+ #error SEEK_CUR != _PDCLIB_SEEK_CUR
+#endif