def __build_libxml2(target, source, env):
    """
    General XSLT builder (HTML/FO), using the libxml2 module.
    """
    xsl_style = env.subst('$DOCBOOK_XSL')
    styledoc = libxml2.parseFile(xsl_style)
    style = libxslt.parseStylesheetDoc(styledoc)
    doc = libxml2.readFile(str(source[0]),None,libxml2.XML_PARSE_NOENT)
    # Support for additional parameters
    parampass = {}
    if parampass:
        result = style.applyStylesheet(doc, parampass)
    else:
        result = style.applyStylesheet(doc, None)
    style.saveResultToFilename(str(target[0]), result, 0)
    style.freeStylesheet()
    doc.freeDoc()
    result.freeDoc()

    return None
General XSLT builder (HTML/FO), using the libxml2 module.