From c82ceee2edce72419959eaf1b980f12251ed008c Mon Sep 17 00:00:00 2001
From: Jan Tojnar <jtojnar@gmail.com>
Date: Wed, 1 Sep 2021 16:26:46 +0200
Subject: [PATCH] vtk_9: fix Qt support

Passing enableQt to the package does not build QVTK and CMake warns:
    Manually-specified variables were not used by the project:
        VTK_Group_Qt
---
 pkgs/development/libraries/vtk/generic.nix | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/libraries/vtk/generic.nix b/pkgs/development/libraries/vtk/generic.nix
index 482e6be7bbcf..fb2b11511b99 100644
--- a/pkgs/development/libraries/vtk/generic.nix
+++ b/pkgs/development/libraries/vtk/generic.nix
@@ -73,8 +73,9 @@ in stdenv.mkDerivation rec {
     "-DCMAKE_INSTALL_LIBDIR=lib"
     "-DCMAKE_INSTALL_INCLUDEDIR=include"
     "-DCMAKE_INSTALL_BINDIR=bin"
+  ] ++ optionals enableQt [
+    "-D${if lib.versionOlder version "9.0" then "VTK_Group_Qt:BOOL=ON" else "VTK_GROUP_ENABLE_Qt:STRING=YES"}"
   ]
-    ++ optionals enableQt [ "-DVTK_Group_Qt:BOOL=ON" ]
     ++ optionals stdenv.isDarwin [ "-DOPENGL_INCLUDE_DIR=${OpenGL}/Library/Frameworks" ]
     ++ optionals enablePython [
       "-DVTK_WRAP_PYTHON:BOOL=ON"