diff --git a/pkgs/development/haskell-modules/lib/compose.nix b/pkgs/development/haskell-modules/lib/compose.nix
index d84c804272db..065dc2dcad86 100644
--- a/pkgs/development/haskell-modules/lib/compose.nix
+++ b/pkgs/development/haskell-modules/lib/compose.nix
@@ -285,7 +285,11 @@ rec {
     enableLibraryProfiling = false;
     isLibrary = false;
     doHaddock = false;
-    postFixup = "rm -rf $out/lib $out/nix-support $out/share/doc";
+    postFixup = drv.postFixup or "" + ''
+
+      # Remove every directory which could have links to other store paths.
+      rm -rf $out/lib $out/nix-support $out/share/doc
+    '';
   });
 
   /* Build a source distribution tarball instead of using the source files