From 95675222972aabef55949c4934923e77cbdffbf6 Mon Sep 17 00:00:00 2001
From: Andreas Fabri <andreas.fabri@geometryfactory.com>
Date: Tue, 19 Apr 2022 17:02:20 +0100
Subject: [PATCH] Include header

---
 Nef_3/include/CGAL/Nef_3/SNC_external_structure.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Nef_3/include/CGAL/Nef_3/SNC_external_structure.h b/Nef_3/include/CGAL/Nef_3/SNC_external_structure.h
index 89e5d17b04d..50074dc6ce7 100644
--- a/Nef_3/include/CGAL/Nef_3/SNC_external_structure.h
+++ b/Nef_3/include/CGAL/Nef_3/SNC_external_structure.h
@@ -30,6 +30,7 @@
 #include <CGAL/Nef_3/SNC_simplify.h>
 #include <map>
 #include <list>
+#include <unordered_map>
 
 #undef CGAL_NEF_DEBUG
 #define CGAL_NEF_DEBUG 43