diff --git a/pkgs/applications/video/mythtv/builder.sh b/pkgs/applications/video/mythtv/builder.sh
index e30fa126f3c7..d3888175bd91 100644
--- a/pkgs/applications/video/mythtv/builder.sh
+++ b/pkgs/applications/video/mythtv/builder.sh
@@ -1,7 +1,5 @@
 . $stdenv/setup
 
-export QTDIR=$qt3
-
 
 buildPhase=myBuilder
 myBuilder() {
diff --git a/pkgs/development/libraries/qt-3/builder.sh b/pkgs/development/libraries/qt-3/builder.sh
index 5273ca795d3d..0af2669ba9b0 100644
--- a/pkgs/development/libraries/qt-3/builder.sh
+++ b/pkgs/development/libraries/qt-3/builder.sh
@@ -1,4 +1,8 @@
 . $stdenv/setup
+. $substitute
+
+ensureDir $out/nix-support
+substitute "$hook" "$out/nix-support/setup-hook" --subst-var out
 
 
 preConfigure=preConfigure
@@ -9,11 +13,9 @@ preConfigure() {
     # will cause ./configure misdetections).
     for i in config.tests/unix/checkavail config.tests/*/*.test mkspecs/*/qmake.conf; do
         echo "patching $i..."
-        sed < $i > $i.tmp \
-            -e 's^ /lib^ /FOO^g' \
-            -e 's^/usr^/FOO^g'
-        if test -x $i; then chmod +x $i.tmp; fi
-        mv $i.tmp $i
+        substituteInPlace "$i" \
+            --replace " /lib" " /FOO" \
+            --replace "/usr" "/FOO"
     done
 }
 
diff --git a/pkgs/development/libraries/qt-3/default.nix b/pkgs/development/libraries/qt-3/default.nix
index 70c692978a61..79bfe004881e 100644
--- a/pkgs/development/libraries/qt-3/default.nix
+++ b/pkgs/development/libraries/qt-3/default.nix
@@ -14,6 +14,8 @@ stdenv.mkDerivation {
   name = "qt-3.3.3";
 
   builder = ./builder.sh;
+  substitute = ../../../build-support/substitute/substitute.sh;
+  hook = ./setup-hook.sh;  
   src = fetchurl {
     url = http://catamaran.labs.cs.uu.nl/dist/tarballs/qt-x11-free-3.3.3.tar.bz2;
     md5 = "3e0a0c8429b0a974b39b5f535ddff01c";
diff --git a/pkgs/development/libraries/qt-3/setup-hook.sh b/pkgs/development/libraries/qt-3/setup-hook.sh
new file mode 100644
index 000000000000..db1a2529ff54
--- /dev/null
+++ b/pkgs/development/libraries/qt-3/setup-hook.sh
@@ -0,0 +1 @@
+export QTDIR=@out@