Function xmlXPathRegisterNs 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn xmlXPathRegisterNs(
    _ctxt: *mut _xmlXPathContext,
    _prefix: *const xmlChar,
    _ns_uri: *const xmlChar,
) -> c_int

Register an XPath namespace.

UPSTREAM-PARITY

int xmlXPathRegisterNs(xmlXPathContextPtr ctxt,
                       const xmlChar *prefix, const xmlChar *ns_uri);