Original commit message from CVS:
Use docbook xsl version 1.50.0 until libxslt can handle 1.51.0 and above
<!-- This file is for customizing the default XSL stylesheets. -->
<!-- We include them here (this one is for HTML output): -->
<xsl:import
- href="http://docbook.sourceforge.net/release/xsl/current/xhtml/chunk.xsl"/>
+ href="http://docbook.sourceforge.net/release/xsl/1.50.0/xhtml/chunk.xsl"/>
<!-- .. and customize them here: -->
<xsl:include href="fileext.xsl"/>