From c9ebad1276cd67df394084eeef30b945dc32816e Mon Sep 17 00:00:00 2001
From: Laurent Rineau <laurent.rineau@cgal.org>
Date: Mon, 25 Jan 2016 16:35:51 +0100
Subject: [PATCH] Fix CGAL_LAZY_KERNEL_DEBUG and boost::optional

---
 Filtered_kernel/include/CGAL/Lazy.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Filtered_kernel/include/CGAL/Lazy.h b/Filtered_kernel/include/CGAL/Lazy.h
index 204a2bf70cd..13412828169 100644
--- a/Filtered_kernel/include/CGAL/Lazy.h
+++ b/Filtered_kernel/include/CGAL/Lazy.h
@@ -37,6 +37,9 @@
 
 #include <boost/optional.hpp>
 #include <boost/variant.hpp>
+#ifdef CGAL_LAZY_KERNEL_DEBUG
+#  include <boost/optional/optional_io.hpp>
+#endif
 
 #include <boost/mpl/has_xxx.hpp>