[styles] Check for listings.sty version 1.6

Author: jensmaurer

source/styles.tex

@@ -154,6 +154,15 @@
 %% override some functions from the listings package to avoid bad page breaks
 %% (copied verbatim from listings.sty version 1.6 except where commented)
 \makeatletter
+
+\lst@CheckVersion{1.6}{\lst@CheckVersion{1.5b}{
+ \typeout{^^J%
+ ***^^J%
+ *** This file requires listings.sty version 1.6.^^J%
+ *** You have version \lst@version; exiting ...^^J%
+ ***^^J}%
+ \batchmode \@@end}}
+
 \def\lst@Init#1{%
     \begingroup
     \ifx\lst@float\relax\else