diff --git a/pkgs/development/libraries/qt-5/5.4/qtbase/default.nix b/pkgs/development/libraries/qt-5/5.4/qtbase/default.nix
index af9b3feb6df0..b22f90d5daf7 100644
--- a/pkgs/development/libraries/qt-5/5.4/qtbase/default.nix
+++ b/pkgs/development/libraries/qt-5/5.4/qtbase/default.nix
@@ -98,8 +98,11 @@ stdenv.mkDerivation {
     export LD_LIBRARY_PATH="$PWD/qtbase/lib:$PWD/qtbase/plugins/platforms:$LD_LIBRARY_PATH"
     export MAKEFLAGS=-j$NIX_BUILD_CORES
 
-    export configureFlags+="-plugindir $out/lib/qt5/plugins -importdir $out/lib/qt5/imports -qmldir $out/lib/qt5/qml"
-    export configureFlags+=" -docdir $out/share/doc/qt5"
+    configureFlags+=" -plugindir $out/lib/qt5/plugins"
+    configureFlags+=" -importdir $out/lib/qt5/imports"
+    configureFlags+=" -qmldir $out/lib/qt5/qml"
+    configureFlags+=" -docdir $out/share/doc/qt5"
+    export configureFlags
   '';
 
   prefixKey = "-prefix ";