Bug #1106572: clarify os.makedirs docs wrt umask
diff --git a/Doc/lib/libos.tex b/Doc/lib/libos.tex
index 50dad08..04acce6 100644
--- a/Doc/lib/libos.tex
+++ b/Doc/lib/libos.tex
@@ -875,7 +875,8 @@
but makes all intermediate-level directories needed to contain the
leaf directory. Throws an \exception{error} exception if the leaf
directory already exists or cannot be created. The default \var{mode}
-is \code{0777} (octal).
+is \code{0777} (octal). On some systems, \var{mode} is ignored.
+Where it is used, the current umask value is first masked out.
\versionadded{1.5.2}
\versionchanged[This function now handles UNC paths correctly]{2.3}
\end{funcdesc}