diff --git a/pkgs/development/libraries/qt-5/5.5/qtx11extras.nix b/pkgs/development/libraries/qt-5/5.5/qtx11extras.nix
index a765161e2d7e..db92f1353627 100644
--- a/pkgs/development/libraries/qt-5/5.5/qtx11extras.nix
+++ b/pkgs/development/libraries/qt-5/5.5/qtx11extras.nix
@@ -3,4 +3,7 @@
 qtSubmodule {
   name = "qtx11extras";
   qtInputs = [ qtbase ];
+  postFixup = ''
+    fixQtModuleCMakeConfig "X11Extras"
+  '';
 }