diff --git a/mingw-w64-headers/crt/ChangeLog b/mingw-w64-headers/crt/ChangeLog
index 91eb049..c717d99 100644
--- a/mingw-w64-headers/crt/ChangeLog
+++ b/mingw-w64-headers/crt/ChangeLog
@@ -1,3 +1,9 @@
+2011-11-14  Ozkan Sezer  <sezeroz@gmail.com>
+
+	* unistd.h: Define SEEK_SET, SEEK_CUR, SEEK_END, STDIN_FILENO,
+	STDOUT_FILENO and STDERR_FILENO, if not already defined. Patch
+	from 'antran'. Closes bug #3426006.
+
 2011-11-13  Kai Tietz  <ktietz@redhat.com>
 
 	* stdio.h, wchar.h:  Replace __forceinline by
diff --git a/mingw-w64-headers/crt/unistd.h b/mingw-w64-headers/crt/unistd.h
index c7f6bc7..9cb791a 100644
--- a/mingw-w64-headers/crt/unistd.h
+++ b/mingw-w64-headers/crt/unistd.h
@@ -11,6 +11,20 @@
 #include <process.h>
 #include <getopt.h>
 
+/* These are also defined in stdio.h. */
+#ifndef SEEK_SET
+#define SEEK_SET 0
+#define SEEK_CUR 1
+#define SEEK_END 2
+#endif
+
+/* These are also defined in stdio.h. */
+#ifndef STDIN_FILENO
+#define STDIN_FILENO  0
+#define STDOUT_FILENO 1
+#define STDERR_FILENO 2
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif