package/bootgen: Re-apply fix build on machines with modern flex

With bootgen 2025.1, the directory structure was re-done.  In the process of
doing this, the source files in the bisonflex directory lost the fix below
which had been applied on an earlier version of bootgen for the issue below.

Bootgen embeds an old version of flex, but uses the system include syntax
(#include <>) to reference it, causing conflicts on systems with the
development headers for a modern flex version installed, leading to build
issues like:

../bisonflex/bif.yy.cpp: In member function 'virtual int BIF::FlexScanner::yylex()':
../bisonflex/bif.yy.cpp:1608:18: error: no match for 'operator=' (operand types are 'std::istream' {aka 'std::basic_istream'} and 'std::istream*' {aka 'std::basic_istream*'})

Fix it by using normal local #include statements by:

sed -i 's/<FlexLexer.h>/"FlexLexer.h"/g' *

This patch re-adds the patch to fix this to buildroot.

Fixes: https://autobuild.buildroot.org/results/056384322246877253cd8d0781717ce495cbe769/
Upstream: patch submitted to AMD internal jira process

Signed-off-by: Neal Frager <neal.frager@amd.com>
Reviewed-By: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/bootgen/0001-bisonflex-Fix-build-on-machines-with-modern-flex.patch

@@ -0,0 +1,72 @@
+From e7e341b7ba6fa9fb875718e8740b03c2041278e8 Mon Sep 17 00:00:00 2001
+From: Neal Frager <neal.frager@amd.com>
+Date: Mon, 2 Jun 2025 12:09:13 +0100
+Subject: [PATCH] bisonflex: Fix build on machines with modern flex
+
+With bootgen 2025.1, the directory structure was re-done.  In the process of
+doing this, the source files in the bisonflex directory lost the fix below
+which had been applied on an earlier version of bootgen:
+
+Bootgen embeds an old version of flex, but uses the system include syntax
+(#include <>) to reference it, causing conflicts on systems with the
+development headers for a modern flex version installed, leading to build
+issues like:
+
+../bisonflex/bif.yy.cpp: In member function 'virtual int BIF::FlexScanner::yylex()':
+../bisonflex/bif.yy.cpp:1608:18: error: no match for 'operator=' (operand types are 'std::istream' {aka 'std::basic_istream'} and 'std::istream*' {aka 'std::basic_istream*'})
+
+Fix it by using normal local #include statements by:
+
+sed -i 's/<FlexLexer.h>/"FlexLexer.h"/g' *
+
+Upstream: submitted to AMD internal jira process
+
+Signed-off-by: Neal Frager <neal.frager@amd.com>
+---
+ bisonflex/bif.yy.cpp        | 2 +-
+ bisonflex/cmdoptions.yy.cpp | 2 +-
+ bisonflex/reginit.yy.cpp    | 2 +-
+ 3 files changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/bisonflex/bif.yy.cpp b/bisonflex/bif.yy.cpp
+index 8d4d364..35f0aa5 100755
+--- a/bisonflex/bif.yy.cpp
++++ b/bisonflex/bif.yy.cpp
+@@ -379,7 +379,7 @@ typedef unsigned char YY_CHAR;
+ 
+ #define yytext_ptr yytext
+ 
+-#include <FlexLexer.h>
++#include "FlexLexer.h"
+ 
+ int yyFlexLexer::yywrap() { return 1; }
+ int yyFlexLexer::yylex()
+diff --git a/bisonflex/cmdoptions.yy.cpp b/bisonflex/cmdoptions.yy.cpp
+index 661d7f3..a76ac81 100755
+--- a/bisonflex/cmdoptions.yy.cpp
++++ b/bisonflex/cmdoptions.yy.cpp
+@@ -379,7 +379,7 @@ typedef unsigned char YY_CHAR;
+ 
+ #define yytext_ptr yytext
+ 
+-#include <FlexLexer.h>
++#include "FlexLexer.h"
+ 
+ int yyFlexLexer::yywrap() { return 1; }
+ int yyFlexLexer::yylex()
+diff --git a/bisonflex/reginit.yy.cpp b/bisonflex/reginit.yy.cpp
+index d830734..dede473 100755
+--- a/bisonflex/reginit.yy.cpp
++++ b/bisonflex/reginit.yy.cpp
+@@ -379,7 +379,7 @@ typedef unsigned char YY_CHAR;
+ 
+ #define yytext_ptr yytext
+ 
+-#include <FlexLexer.h>
++#include "FlexLexer.h"
+ 
+ int yyFlexLexer::yywrap() { return 1; }
+ int yyFlexLexer::yylex()
+-- 
+2.25.1
+