railsetup required for IsarRef/style;

--- a/doc-src/System/system.tex	Tue May 03 21:55:19 2011 +0200
+++ b/doc-src/System/system.tex	Tue May 03 22:26:16 2011 +0200
@@ -4,6 +4,7 @@
 \usepackage{../iman,../extra,../isar,../ttbox}
 \usepackage[nohyphen,strings]{../underscore}
 \usepackage{../../lib/texinputs/isabelle,../../lib/texinputs/isabellesym}
+\usepackage{../../lib/texinputs/railsetup}
 \usepackage{../IsarRef/style}
 \usepackage{../pdfsetup}