checkpatch: Do not allow deprecated g_memdup()

g_memdup() is insecure and as been deprecated in GLib 2.68.
QEMU provides the safely equivalent g_memdup2() wrapper.

Do not allow more g_memdup() calls in the repository, provide
a hint to use g_memdup2().

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210903174510.751630-29-philmd@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

scripts/checkpatch.pl

@@ -2850,6 +2850,11 @@ sub process {
 			WARN("consider using g_path_get_$1() in preference to g_strdup($1())\n" . $herecurr);
 		}
 
+# enforce g_memdup2() over g_memdup()
+		if ($line =~ /\bg_memdup\s*\(/) {
+			ERROR("use g_memdup2() instead of unsafe g_memdup()\n" . $herecurr);
+		}
+
 # recommend qemu_strto* over strto* for numeric conversions
 		if ($line =~ /\b(strto[^kd].*?)\s*\(/) {
 			ERROR("consider using qemu_$1 in preference to $1\n" . $herecurr);