diff -ru5 qtwebkit-2.3.4old/Source/WebCore/css/makegrammar.pl qtwebkit-2.3.4/Source/WebCore/css/makegrammar.pl
--- qtwebkit-2.3.4old/Source/WebCore/css/makegrammar.pl	2014-09-24 13:42:05.000000000 +0200
+++ qtwebkit-2.3.4/Source/WebCore/css/makegrammar.pl	2021-01-15 16:26:26.143592480 +0100
@@ -71,25 +71,8 @@
 
     exit if $preprocessOnly;
 }
 
 my $fileBase = File::Spec->join($outputDir, $filename);
-system("$bison -d -p $symbolsPrefix $grammarFilePath -o $fileBase.cpp");
-
-open HEADER, ">$fileBase.h" or die;
-print HEADER << "EOF";
-#ifndef CSSGRAMMAR_H
-#define CSSGRAMMAR_H
-EOF
-
-open HPP, "<$fileBase.cpp.h" or open HPP, "<$fileBase.hpp" or die;
-while (<HPP>) {
-    print HEADER;
-}
-close HPP;
-
-print HEADER "#endif\n";
-close HEADER;
-
-unlink("$fileBase.cpp.h");
-unlink("$fileBase.hpp");
-
+my @bisonCommand = ($bison, "--defines=$fileBase.h", "-p", $symbolsPrefix, $grammarFilePath, "-o", "$fileBase.cpp");
+push @bisonCommand, "--no-lines" if $^O eq "MSWin32"; # Work around bug in bison >= 3.0 on Windows where it puts backslashes into #line directives.
+system(@bisonCommand) == 0 or die;
diff -ru5 qtwebkit-2.3.4old/Source/WebCore/xml/XPathGrammar.y qtwebkit-2.3.4/Source/WebCore/xml/XPathGrammar.y
--- qtwebkit-2.3.4old/Source/WebCore/xml/XPathGrammar.y	2014-09-24 13:42:05.000000000 +0200
+++ qtwebkit-2.3.4/Source/WebCore/xml/XPathGrammar.y	2021-01-15 16:24:12.742509253 +0100
@@ -51,10 +51,11 @@
 
 %}
 
 %pure_parser
 %parse-param { WebCore::XPath::Parser* parser }
+%define api.header.include { "XPathGrammar.h" }
 
 %union
 {
     Step::Axis axis;
     Step::NodeTest* nodeTest;