boot/syslinux: fix building with GCC 14.x

Add missing stdio.h include. Without this includes, the build fails
with the following error under GCC 14.x:

../../../com32/lib/syslinux/debug.c: In function ‘syslinux_debug’:
../../../com32/lib/syslinux/debug.c:91:5: error: implicit declaration of function ‘printf’ [-Wimplicit-function-declaration]
   91 |     printf("Dynamic debug unavailable\n");

Signed-off-by: Lance Fredrickson <lancethepants@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 3b9d62dac564b6d1bfa5ba5e0dd72e731fd95d55)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

boot/syslinux/0020-pull-in-stdio-h-for-gcc14.patch

@@ -0,0 +1,34 @@
+From dfa2705100a893bc017d23406daa9a383fbc3c95 Mon Sep 17 00:00:00 2001
+From: Lance Fredrickson <lancethepants@gmail.com>
+Date: Wed, 5 Jun 2024 14:31:38 -0600
+Subject: [PATCH] com32/lib/syslinux/debug.c: add missing stdio.h include.
+
+Fix building syslinux with GCC 14.x
+
+Add missing stdio.h include. Without it results in the following error under GCC 14.x
+
+../../../com32/lib/syslinux/debug.c: In function ‘syslinux_debug’:
+../../../com32/lib/syslinux/debug.c:91:5: error: implicit declaration of function ‘printf’ [-Wimplicit-function-declaration]
+   91 |     printf("Dynamic debug unavailable\n");
+
+Upstream: dead (last release in 2014)
+Signed-off-by: Lance Fredrickson <lancethepants@gmail.com>
+---
+ com32/lib/syslinux/debug.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/com32/lib/syslinux/debug.c b/com32/lib/syslinux/debug.c
+index d9ab863f..e8f53d57 100644
+--- a/com32/lib/syslinux/debug.c
++++ b/com32/lib/syslinux/debug.c
+@@ -1,6 +1,7 @@
+ #include <linux/list.h>
+ #include <string.h>
+ #include <stdbool.h>
++#include <stdio.h>
+ 
+ #ifdef DYNAMIC_DEBUG
+ 
+-- 
+2.39.2
+