diff --git a/srcpkgs/qt5-webkit/patches/include_functional.diff b/srcpkgs/qt5-webkit/patches/include_functional.diff
new file mode 100644
index 00000000000..542cb19f90b
--- /dev/null
+++ b/srcpkgs/qt5-webkit/patches/include_functional.diff
@@ -0,0 +1,14 @@
+Description: add missing #include <functional>
+Origin: upstream, https://github.com/annulen/webkit/commit/4ce8ebc4094512b9
+Last-Update: 2018-04-15
+
+--- Source/WebCore/dom/SlotAssignment.h
++++ Source/WebCore/dom/SlotAssignment.h
+@@ -28,6 +28,7 @@
+ 
+ #if ENABLE(SHADOW_DOM) || ENABLE(DETAILS_ELEMENT)
+ 
++#include <functional>
+ #include <wtf/HashMap.h>
+ #include <wtf/HashSet.h>
+ #include <wtf/Vector.h>