package/bootgen: fix path to local FlexLexer.h

With bootgen xilinx_v2025.1, the local FlexLexer.h file is not in the same
directory as the cpp files including it, so the previous patch used to solve
the issue below needs to be updated to find the local FlexLexer.h which is in
the win_include directory of bootgen version xilinx_v2025.1.
See upstream commit [1].

So this patch corrects the path for including the local FlexLexer.h header for
fixing the below issue.

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*'})

This build failure can also happen if the host-flex Buildroot package
is built before host-bootgen.

The failure can be reproduced, in the Buildroot docker reference image
with the commands:

    utils/docker-run
    make versal_vck190_defconfig
    make host-flex host-bootgen

Fix it by using normal local #include statements by:

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

Fixes: https://autobuild.buildroot.org/results/60220f94cca1bcca5667afcb2acffb5aacae048b

[1] https://github.com/Xilinx/bootgen/commit/86b862096bcbdb45d4ce1504ecfe90fb29f318a5#diff-0d754a86508dc8a894b72796966f332c0316942c5d5ab42ae6a0766dcfcb52dc

Signed-off-by: Neal Frager <neal.frager@amd.com>
[Julien: add extra info in commit log]
Signed-off-by: Julien Olivain <ju.o@free.fr>

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

@@ -17,7 +17,7 @@ issues like:
 
 Fix it by using normal local #include statements by:
 
-sed -i 's/<FlexLexer.h>/"FlexLexer.h"/g' *
+sed -i 's/<FlexLexer.h>/"../win_include/FlexLexer.h"/g' *
 
 Upstream: submitted to AMD internal jira process
 
@@ -37,7 +37,7 @@ index 8d4d364..35f0aa5 100755
  #define yytext_ptr yytext
  
 -#include <FlexLexer.h>
-+#include "FlexLexer.h"
++#include "../win_include/FlexLexer.h"
  
  int yyFlexLexer::yywrap() { return 1; }
  int yyFlexLexer::yylex()
@@ -50,7 +50,7 @@ index 661d7f3..a76ac81 100755
  #define yytext_ptr yytext
  
 -#include <FlexLexer.h>
-+#include "FlexLexer.h"
++#include "../win_include/FlexLexer.h"
  
  int yyFlexLexer::yywrap() { return 1; }
  int yyFlexLexer::yylex()
@@ -63,7 +63,7 @@ index d830734..dede473 100755
  #define yytext_ptr yytext
  
 -#include <FlexLexer.h>
-+#include "FlexLexer.h"
++#include "../win_include/FlexLexer.h"
  
  int yyFlexLexer::yywrap() { return 1; }
  int yyFlexLexer::yylex()