diff --git a/pkgs/desktops/deepin/dtkwm/default.nix b/pkgs/desktops/deepin/dtkwm/default.nix
index bc51c3dd7b4..c05eedd8857 100644
--- a/pkgs/desktops/deepin/dtkwm/default.nix
+++ b/pkgs/desktops/deepin/dtkwm/default.nix
@@ -23,12 +23,13 @@ mkDerivation rec {
     qtx11extras
   ];
 
-  preConfigure = ''
-    qmakeFlags="$qmakeFlags \
-      QT_HOST_DATA=$out \
-      INCLUDE_INSTALL_DIR=$out/include \
-      LIB_INSTALL_DIR=$out/lib"
-  '';
+  outRef = placeholder "out";
+
+  qmakeFlags = [
+    "QT_HOST_DATA=${outRef}"
+    "INCLUDE_INSTALL_DIR=${outRef}/include"
+    "LIB_INSTALL_DIR=${outRef}/lib"
+  ];
 
   passthru.updateScript = deepin.updateScript { inherit name; };