diff -up plasma-desktop-5.8.5/imports/activitymanager/sortedactivitiesmodel.cpp.than plasma-desktop-5.8.5/imports/activitymanager/sortedactivitiesmodel.cpp
--- plasma-desktop-5.8.5/imports/activitymanager/sortedactivitiesmodel.cpp.than	2017-02-13 11:05:27.199853397 -0500
+++ plasma-desktop-5.8.5/imports/activitymanager/sortedactivitiesmodel.cpp	2017-02-13 11:36:19.952794792 -0500
@@ -17,6 +17,8 @@
  *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
+#include <functional>
+
 // Self
 #include "sortedactivitiesmodel.h"