Load the minimal class in chkconfig.ltx

Otherwise some packages (e.g. babel and xkeyval) error on checking

lib/chkconfig.ltx

@@ -60,6 +60,11 @@
 %   the variable chk_<name>.
 %%%
 
+% we need to load the minmal class
+% since some packages will error out
+% on checking of no class is loaded
+\documentclass{minimal}
+
 \newcommand{\prefix}{+} % the character used by grep to filter 'good' output
 
 \newcommand{\AddLayout}[5][\default]{