From 08bbe0820556e1e98212db9d91fca1e035211598 Mon Sep 17 00:00:00 2001
From: James Turner <james@flightgear.org>
Date: Fri, 14 Aug 2020 21:16:37 +0100
Subject: [PATCH] Missed include for Linux

---
 simgear/scene/material/matmodel.cxx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/simgear/scene/material/matmodel.cxx b/simgear/scene/material/matmodel.cxx
index c45446e0..2767322a 100644
--- a/simgear/scene/material/matmodel.cxx
+++ b/simgear/scene/material/matmodel.cxx
@@ -28,7 +28,7 @@
 #include <simgear/compiler.h>
 
 #include <map>
-
+#include <mutex>
 
 #include <osg/AlphaFunc>
 #include <osg/Group>