From 67a52efc1f44289471fdbb9feef8dfbd2bfec423 Mon Sep 17 00:00:00 2001
From: Jane Tournois <jane.tournois@geometryfactory.com>
Date: Tue, 19 Jan 2016 15:22:08 +0100
Subject: [PATCH] Less should derive from std::unary_function

otherwise the type name Less_than::argument_type is invalid
and causes compilation errors
---
 Mesh_3/include/CGAL/Gray_image_mesh_domain_3.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Mesh_3/include/CGAL/Gray_image_mesh_domain_3.h b/Mesh_3/include/CGAL/Gray_image_mesh_domain_3.h
index 008a6d715c2..0828e9e0aab 100644
--- a/Mesh_3/include/CGAL/Gray_image_mesh_domain_3.h
+++ b/Mesh_3/include/CGAL/Gray_image_mesh_domain_3.h
@@ -35,7 +35,7 @@ namespace CGAL {
 namespace internal {
 
 template<typename T>
-struct Less_than {
+struct Less_than : public std::unary_function<T, bool> {
   Less_than(const T& second) : second(second) {}
   bool operator()(const T& first) const { return std::less<T>()(first, second); }
   T second;