--- gnucash/gnome/window-reconcile.cpp.orig
+++ gnucash/gnome/window-reconcile.cpp
@@ -38,6 +38,7 @@
 #include <gdk/gdkkeysyms.h>
 
 #include <algorithm>
+#include <unordered_map>
 
 #include "Account.hpp"
 #include "Scrub.h"