Added SEEK_* constants. Fixes #711830.
diff --git a/Doc/lib/libos.tex b/Doc/lib/libos.tex
index b1c06b1..995e432 100644
--- a/Doc/lib/libos.tex
+++ b/Doc/lib/libos.tex
@@ -636,6 +636,15 @@
Availability: Windows.
\end{datadesc}
+\begin{datadesc}{SEEK_SET}
+\dataline{SEEK_CUR}
+\dataline{SEEK_END}
+Parameteters to the \function{lseek()} function.
+Their values are 0, 1, and 2, respectively.
+Availability: Windows, Macintosh, \UNIX.
+\versionadded{2.5}
+\end{datadesc}
+
\subsection{Files and Directories \label{os-file-dir}}
\begin{funcdesc}{access}{path, mode}