+% Needed to perform division in the definition of \singleblskip.
+\usepackage{calc}
+
+% A \baselineskip without the \baselinestretch scaling factor. Even
+% though \baselinestretch defaults to 1.0, it doesn't really have that
+% value. Thus to avoid division by zero, we need to do the ``is this
+% thing empty?'' hack.
+%
+% If we use \baselineskip instead of \singleblskip in our list, things
+% get real ugly when the text is e.g. double-spaced.
+%
+\newlength{\singleblskip}
+\setlength{\singleblskip}{
+ \baselineskip / \real{
+ \if\relax\detokenize{\baselinestretch}\relax
+ \baselinestretch%
+ \else
+ 1%
+ \fi}
+}
+