Fix typo reported by Gerry Weiner <gerry@ucar.edu>.
diff --git a/Doc/lib/libposix.tex b/Doc/lib/libposix.tex
index e5108db..acae9af 100644
--- a/Doc/lib/libposix.tex
+++ b/Doc/lib/libposix.tex
@@ -53,8 +53,7 @@
\emph{However:} If you are using this module via the \module{os}
module (as you should -- see the introduction above), \code{environ}
is a a mapping object that behaves almost like a dictionary but
-invokes \function{putenv()} automatically called whenever an item is
-changed.
+invokes \function{putenv()} automatically whenever an item is changed.
\end{datadesc}
\begin{excdesc}{error}