Fix copy construction of LRU cache

include/boost/compute/detail/lru_cache.hpp

@@ -39,6 +39,39 @@ class lru_cache
     {
     }
 
+    // in case of default copying list iterators would be invalidated
+    lru_cache(const lru_cache& other)
+    {
+        lru_cache::operator=(other);
+    }
+
+    lru_cache& operator=(const lru_cache& other)
+    {
+        if(this != &other){
+            m_list = other.m_list;
+            m_capacity = other.m_capacity;
+            for(typename list_type::iterator i = m_list.begin(); i != m_list.end(); ++i){
+                m_map[*i] = std::make_pair(other.m_map.at(*i).first, i);
+            }
+        }
+        return *this;
+    }
+
+    lru_cache(const lru_cache&& other) BOOST_NOEXCEPT
+    {
+        lru_cache::operator=(std::move(other));
+    }
+
+    lru_cache& operator==(lru_cache&& other) BOOST_NOEXCEPT
+    {
+        if(this != &other){
+            m_map = std::move(other.m_map);
+            m_list = std::move(other.m_list);
+            m_capacity = other.m_capacity;
+        }
+        return *this;
+    }
+
     ~lru_cache()
     {
     }