[docbook-apps] webhelp sample build.xml: missing Xerces config?

[Denis Bradford <denis.bradford@verizon.net>]

In docbook-xsl-ns-1.78.1 (and going back to 1.77.1, I think), I've found 
a possible bug in the sample webhelp/build.xml Ant file.

In the chunk target, the first xslt task, which generates a profiled 
version of the document, specifies the Xerces XML parser:

<sysproperty key="org.apache.xerces.xni.parser.XMLParserConfiguration" 
value="org.apache.xerces.parsers.XIncludeParserConfiguration"/>

A second xslt task processes the profiled document to generate the final 
output, but it has no Xerces key. I find that this causes my olinks to 
fail to resolve - haven't looked for any other side effects.

When I copied this sysproperty task to the second xslt task, the olinks 
resolved.