Use %pure-parser in grammar files to make Bison 3 happy.

Source/core/xml/XPathGrammar.y

 /*
  * Copyright 2005 Frerich Raabe <raabe@kde.org>
  * Copyright (C) 2006 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 
  * 1. Redistributions of source code must retain the above copyright
@@ skipping 33 matching lines @@
 #define YYENABLE_NLS 0
 #define YYLTYPE_IS_TRIVIAL 1
 #define YYDEBUG 0
 #define YYMAXDEPTH 10000
 
 using namespace WebCore;
 using namespace XPath;
 
 %}
 
-%pure_parser
+%pure-parser
 %parse-param { WebCore::XPath::Parser* parser }
 
 %union
 {
     Step::Axis axis;
     Step::NodeTest* nodeTest;
     NumericOp::Opcode numop;
     EqTestOp::Opcode eqop;
     String* str;
     Expression* expr;
@@ skipping 480 matching lines @@
     MINUS UnaryExpr
     {
         $$ = new Negative;
         $$->addSubExpression(adoptPtr($2));
         parser->unregisterParseNode($2);
         parser->registerParseNode($$);
     }
     ;
 
 %%