Fix build with Bison 3.7

https://bugs.gentoo.org/736499

Patch copied from upstream source repository:

https://github.com/qtwebkit/qtwebkit/commit/d92b11fea65364fefa700249bd3340e0cd4c5b31

From d92b11fea65364fefa700249bd3340e0cd4c5b31 Mon Sep 17 00:00:00 2001
From: Dmitry Shachnev <mitya57@gmail.com>
Date: Tue, 4 Aug 2020 21:04:06 +0300
Subject: [PATCH] Let Bison generate the header directly, to fix build with
 Bison 3.7

Starting with Bison 3.7, the generated C++ file #include's the header
by default, instead of duplicating it. So we should not delete it.

Remove the code to add #ifdef guards to the header, since Bison adds
them itself since version 2.6.3.
---
 Source/WebCore/css/makegrammar.pl | 21 +--------------------
 1 file changed, 1 insertion(+), 20 deletions(-)

diff --git a/Source/WebCore/css/makegrammar.pl b/Source/WebCore/css/makegrammar.pl
index 5d63b08102eb5..9435701c70612 100644
--- a/Source/WebCore/css/makegrammar.pl
+++ b/Source/WebCore/css/makegrammar.pl
@@ -73,25 +73,6 @@
 }
 
 my $fileBase = File::Spec->join($outputDir, $filename);
-my @bisonCommand = ($bison, "-d", "-p", $symbolsPrefix, $grammarFilePath, "-o", "$fileBase.cpp");
+my @bisonCommand = ($bison, "--defines=$fileBase.h", "-p", $symbolsPrefix, $grammarFilePath, "-o", "$fileBase.cpp");
 push @bisonCommand, "--no-lines" if $^O eq "MSWin32"; # Work around bug in bison >= 3.0 on Windows where it puts backslashes into #line directives.
 system(@bisonCommand) == 0 or die;
-
-open HEADER, ">$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");
-
e='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=b6a1cc89d4d01ee9272a8046985bb1ff9b15eb3a'>root</a>/<a href='/guix/log/etc?id=b6a1cc89d4d01ee9272a8046985bb1ff9b15eb3a'>etc</a>/<a href='/guix/log/etc/system-tests.scm?id=b6a1cc89d4d01ee9272a8046985bb1ff9b15eb3a'>system-tests.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/etc/system-tests.scm?id=b6a1cc89d4d01ee9272a8046985bb1ff9b15eb3a&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-03-23 00:06:58 +0100'>2020-03-23</span></td><td><a href='/guix/commit/etc/system-tests.scm?id=8b18f5cb309f670b08ad35df6425f4e9e19d8a82'>tests: Use the same source as ci.guix.gnu.org.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/system-tests.scm (system-test-manifest): In 'local-file' call, use
a name that is a function of COMMIT to match what Cuirass does.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-03-05 16:33:38 +0100'>2020-03-05</span></td><td><a href='/guix/commit/etc/system-tests.scm?id=5ec4156bbcaec8337f78411204d59e59e706103b'>tests: Add a manifest for system tests.</a><span class='msg-avail'>...<span class='msg-tooltip'>The manifest can be passed to 'guix build -m', 'guix weather -m', and so
on.  It can also be passed to an installed 'guix' (without
./pre-inst-env), with the exception so far of installation tests.

* build-aux/run-system-tests.scm: Remove.  Move interesting bits move
to...
* etc/system-tests.scm: ... here.  New file.
* Makefile.am (EXTRA_DIST): Remove 'build-aux/run-system-tests.scm' and
add 'etc/system-tests.scm'.
(check-system): Rewrite to run 'guix build -m etc/system-tests.scm'.
</span></span></td><td>Ludovic Courtès</td></tr>