diff --git a/pkgs/development/libraries/qt-4.x/4.8/default.nix b/pkgs/development/libraries/qt-4.x/4.8/default.nix
index b03b8896a5fc..46bb7a4e8faa 100644
--- a/pkgs/development/libraries/qt-4.x/4.8/default.nix
+++ b/pkgs/development/libraries/qt-4.x/4.8/default.nix
@@ -54,6 +54,12 @@ stdenv.mkDerivation rec {
     # there might be more references, but this is the only one I could find
     substituteInPlace tools/macdeployqt/tests/tst_deployment_mac.cpp \
       --replace /usr/lib/libstdc++.6.dylib "${stdenv.cc}/lib/libstdc++.6.dylib"
+  '' + stdenv.lib.optionalString stdenv.cc.isClang ''
+    substituteInPlace src/3rdparty/webkit/Source/WebCore/html/HTMLImageElement.cpp \
+      --replace 'optionalHeight > 0' 'optionalHeight != NULL'
+
+    substituteInPlace ./tools/linguist/linguist/messagemodel.cpp \
+      --replace 'm->comment()) >= 0' 'm->comment()) != NULL'
   '';
 
   patches =