From 70467a31dc6b4d31712a367e5e98ccc9bf4ac3cf Mon Sep 17 00:00:00 2001
From: Robbert van der Helm <mail@robbertvanderhelm.nl>
Date: Sun, 30 May 2021 17:54:45 +0200
Subject: [PATCH] Fix compilation under GCC 11

---
 src/common/bitsery/ext/message-reference.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/common/bitsery/ext/message-reference.h b/src/common/bitsery/ext/message-reference.h
index e2da77a0..cf43ebe1 100644
--- a/src/common/bitsery/ext/message-reference.h
+++ b/src/common/bitsery/ext/message-reference.h
@@ -17,6 +17,8 @@
 
 #pragma once
 
+#include <optional>
+
 #include <bitsery/details/serialization_common.h>
 #include <bitsery/traits/core/traits.h>