Mark TMPDIR correctly.
diff --git a/Doc/lib/libtempfile.tex b/Doc/lib/libtempfile.tex
index d81084e..93577e7 100644
--- a/Doc/lib/libtempfile.tex
+++ b/Doc/lib/libtempfile.tex
@@ -26,12 +26,11 @@
\begin{datadesc}{tempdir}
When set to a value other than \code{None}, this variable defines the
directory in which filenames returned by \function{mktemp()} reside.
-The default is taken from the environment variable \code{TMPDIR}; if
+The default is taken from the environment variable \envvar{TMPDIR}; if
this is not set, either \file{/usr/tmp} is used (on \UNIX{}), or the
current working directory (all other systems). No check is made to
see whether its value is valid.
\end{datadesc}
-\ttindex{TMPDIR}
\begin{datadesc}{template}
When set to a value other than \code{None}, this variable defines the
diff --git a/Doc/libtempfile.tex b/Doc/libtempfile.tex
index d81084e..93577e7 100644
--- a/Doc/libtempfile.tex
+++ b/Doc/libtempfile.tex
@@ -26,12 +26,11 @@
\begin{datadesc}{tempdir}
When set to a value other than \code{None}, this variable defines the
directory in which filenames returned by \function{mktemp()} reside.
-The default is taken from the environment variable \code{TMPDIR}; if
+The default is taken from the environment variable \envvar{TMPDIR}; if
this is not set, either \file{/usr/tmp} is used (on \UNIX{}), or the
current working directory (all other systems). No check is made to
see whether its value is valid.
\end{datadesc}
-\ttindex{TMPDIR}
\begin{datadesc}{template}
When set to a value other than \code{None}, this variable defines the