Function xmlXPathRegisterVariable 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn xmlXPathRegisterVariable(
    _ctxt: *mut _xmlXPathContext,
    _name: *const xmlChar,
    _value: *mut _xmlXPathObject,
) -> c_int

Register an XPath variable.

UPSTREAM-PARITY

int xmlXPathRegisterVariable(xmlXPathContextPtr ctxt,
                             const xmlChar *name, xmlXPathObjectPtr value);