Add new constants usable with os.popen() on Windows.

NOTE:  this seems a mess wrt which symbols are available on which
platforms.  I can't fix it, but I didn't add to it <wink>, and
included an XXX comment about names claimed to be available on
Windows that aren't.  If anyone can figure out the whole ugly truth,
I'm sure a better organization will suggest itself.

Doc/lib/libos.tex

@@ -531,6 +531,7 @@ The following data items are available for use in constructing the
 Options for the \var{flag} argument to the \function{open()} function.
 These can be bit-wise OR'd together.
 Availability: Macintosh, \UNIX, Windows.
+% XXX O_NDELAY, O_NONBLOCK, O_DSYNC, O_RSYNC, O_SYNC, O_NOCTTY are not on Windows.
 \end{datadesc}
 
 \begin{datadesc}{O_BINARY}
@@ -540,6 +541,16 @@ Availability: Macintosh, Windows.
 % XXX need to check on the availability of this one.
 \end{datadesc}
 
+\begin{datadesc}{O_NOINHERIT}
+\dataline{O_SHORT_LIVED}
+\dataline{O_TEMPORARY}
+\dataline{O_RANDOM}
+\dataline{O_SEQUENTIAL}
+\dataline{O_TEXT}
+Options for the \var{flag} argument to the \function{open()} function.
+These can be bit-wise OR'd together.
+Availability: Windows.
+\end{datadesc}
 
 \subsection{Files and Directories \label{os-file-dir}}