In the below example, I would expect the output (both Sablot and MSXSL 
return this)
<IMG a="">

Instead libxslt returns: (version info below) 
<IMG a>
---------------------------------------------

<?xml version="1.0"?>
<xsl:stylesheet version="1.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="html" indent="yes" omit-xml-declaration="yes"/>
<xsl:template match="/">
<IMG a=""/>
</xsl:template>
</xsl:stylesheet>

------------------
version info

Using libxml 20412, libxslt 10009 and libexslt 702
xsltproc was compiled against libxml 20412, libxslt 10009 and libexslt 702
libxslt 10009 was compiled against libxml 20412
libexslt 702 was compiled against libxml 20412