diff --git a/pkgs/development/libraries/qt-5/5.9/qtwebengine/default.nix b/pkgs/development/libraries/qt-5/5.9/qtwebengine/default.nix
index f001f64db3f..c0b9aa83e19 100644
--- a/pkgs/development/libraries/qt-5/5.9/qtwebengine/default.nix
+++ b/pkgs/development/libraries/qt-5/5.9/qtwebengine/default.nix
@@ -101,9 +101,6 @@ qtSubmodule {
   ];
   patches = optional stdenv.needsPax ./qtwebengine-paxmark-mksnapshot.patch;
 
-  # NSS header layout change
-  NIX_CFLAGS_COMPILE = [ "-I${nss.dev}/include/nss" ];
-
   dontUseNinjaBuild = true;
   dontUseNinjaInstall = true;