From e6caf52f64d5a6347913a0d75c68edf63a66a302 Mon Sep 17 00:00:00 2001
From: Jan Tojnar <jtojnar@gmail.com>
Date: Wed, 1 Sep 2021 17:04:55 +0200
Subject: [PATCH] vtk_9: do not vendor libpng and libtiff

Previously ldd did not show the dependencies so presumably,
VTK 9 started linking them statically after build system changes,
as hinted by the following CMake warning:
    Manually-specified variables were not used by the project:
        VTK_USE_SYSTEM_PNG
        VTK_USE_SYSTEM_TIFF
---
 pkgs/development/libraries/vtk/generic.nix | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pkgs/development/libraries/vtk/generic.nix b/pkgs/development/libraries/vtk/generic.nix
index fb2b11511b99..a3d3824a5410 100644
--- a/pkgs/development/libraries/vtk/generic.nix
+++ b/pkgs/development/libraries/vtk/generic.nix
@@ -67,8 +67,8 @@ in stdenv.mkDerivation rec {
   cmakeFlags = [
     "-DCMAKE_C_FLAGS=-fPIC"
     "-DCMAKE_CXX_FLAGS=-fPIC"
-    "-DVTK_USE_SYSTEM_PNG=ON"
-    "-DVTK_USE_SYSTEM_TIFF=1"
+    "-D${if lib.versionOlder version "9.0" then "VTK_USE_SYSTEM_PNG" else "VTK_MODULE_USE_EXTERNAL_vtkpng"}=ON"
+    "-D${if lib.versionOlder version "9.0" then "VTK_USE_SYSTEM_TIFF" else "VTK_MODULE_USE_EXTERNAL_vtktiff"}=1"
     "-DOPENGL_INCLUDE_DIR=${libGL}/include"
     "-DCMAKE_INSTALL_LIBDIR=lib"
     "-DCMAKE_INSTALL_INCLUDEDIR=include"