diff --git a/pkgs/development/haskell-modules/make-package-set.nix b/pkgs/development/haskell-modules/make-package-set.nix
index 5215fe4a552..562042721e7 100644
--- a/pkgs/development/haskell-modules/make-package-set.nix
+++ b/pkgs/development/haskell-modules/make-package-set.nix
@@ -44,6 +44,7 @@ let
       isLibrary = false;
       doHaddock = false;
       hyperlinkSource = false;      # Avoid depending on hscolour for this build.
+      enableSeparateEtcOutput = false; # The flag to support this is missing in old versions of cabal.
       postFixup = "rm -rf $out/lib $out/share $out/nix-support";
     });
     cpphs = overrideCabal (self.cpphs.overrideScope (self: super: {