amarok: fix building against Qt-5.11

pkgs/applications/audio/amarok/kf5.nix

@@ -21,6 +21,8 @@ in mkDerivation {
     sha256 = "05w7kl6qfmkjz0y1bhgkkbmsqdll30bkjd6npkzvivrvp7dplmbh";
   };
 
+  patches = [ ./qt5_11.patch ];
+
   nativeBuildInputs = [ extra-cmake-modules kdoctools ];
   propagatedBuildInputs = [
     qca-qt5 qjson qtscript qtwebkit

pkgs/applications/audio/amarok/qt5_11.patch

@@ -0,0 +1,11 @@
+--- a/src/aboutdialog/ExtendedAboutDialog.cpp
++++ b/src/aboutdialog/ExtendedAboutDialog.cpp
+@@ -30,6 +30,7 @@
+ #include <QLayout>
+ #include <QPushButton>
+ #include <QScrollBar>
++#include <QStyle>
+ #include <QTabWidget>
+ 
+ #include <qapplication.h>
+