fixing #61290 "namespace nodes have no parent" long standing divergence

* xpath.c: fixing #61290 "namespace nodes have no parent"
  long standing divergence from the XPath REC. NodeSets
  simply hold a copy of namespace nodes and those node ->next
  points to the parent (which may not be the node carrying the
  definition).
* include/libxml/xpath.h: flagged but didn't added a possible
  speedup
* DOCBparser.c HTMLparser.c: removed some warnings from push
  parser due to new state being added.
* tree.c: new fix from Boris Erdmann
* configure.in c14n.c include/libxml/c14n.h testC14N.c: added
  the XML Canonalization support from Aleksey Sanin
Daniel

HTMLparser.c

@@ -4605,6 +4605,17 @@ htmlParseTryOrFinish(htmlParserCtxtPtr ctxt, int terminate) {
 			"HPP: entering CONTENT\n");
 #endif
 		break;
+	    case XML_PARSER_PUBLIC_LITERAL:
+		xmlGenericError(xmlGenericErrorContext,
+			"HPP: internal error, state == XML_PARSER_LITERAL\n");
+		ctxt->instate = XML_PARSER_CONTENT;
+		ctxt->checkIndex = 0;
+#ifdef DEBUG_PUSH
+		xmlGenericError(xmlGenericErrorContext,
+			"HPP: entering CONTENT\n");
+#endif
+		break;
+
 	}
     }
 done: