diff --git a/pkgs/tools/graphics/gmic-qt/default.nix b/pkgs/tools/graphics/gmic-qt/default.nix
index b301ddaf0ff..65b88b4b15a 100644
--- a/pkgs/tools/graphics/gmic-qt/default.nix
+++ b/pkgs/tools/graphics/gmic-qt/default.nix
@@ -6,8 +6,6 @@
 let
   version = "2.3.6";
 
-  gmic-version = "2.3.6";
-
 in stdenv.mkDerivation rec {
   name = "gmic-qt-${version}";
 
@@ -51,10 +49,13 @@ in stdenv.mkDerivation rec {
     chmod -R +w gmic gmic_qt
     ln -s ${CImg} CImg
 
+    cd gmic_qt
+  '';
+
+  preConfigure = ''
     cp ${gmic_stdlib} gmic/src/gmic_stdlib.h
 
     make -C gmic/src CImg.h gmic_stdlib.h
-    cd gmic_qt
   '';
 
   nativeBuildInputs = [ cmake pkgconfig ];