--- /dev/null
+--- XQilla-2.3.4/include/xqilla/ast/XQDocumentOrder.hpp.orig 2018-07-03 20:37:15.000000000 +0200
++++ XQilla-2.3.4/include/xqilla/ast/XQDocumentOrder.hpp 2022-09-25 20:51:54.768846899 +0200
+@@ -68,7 +68,7 @@ private:
+ public:
+ uniqueLessThanCompareFn(const DynamicContext *context)
+ : context_(context) {}
+- bool operator()(const Node::Ptr &first, const Node::Ptr &second)
++ bool operator()(const Node::Ptr &first, const Node::Ptr &second) const
+ {
+ return first->uniqueLessThan(second, context_);
+ }