From 342e71ba921c6a2591f3d1d01e754959cc378b2a Mon Sep 17 00:00:00 2001
From: Peter Simons <simons@cryp.to>
Date: Wed, 4 Dec 2013 00:15:24 +0100
Subject: [PATCH] haskell-src-exts: clean out the obsolete happy parser that's
 included in the distribution tarball

---
 pkgs/development/libraries/haskell/haskell-src-exts/default.nix | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pkgs/development/libraries/haskell/haskell-src-exts/default.nix b/pkgs/development/libraries/haskell/haskell-src-exts/default.nix
index 16595e331565..b044437e527a 100644
--- a/pkgs/development/libraries/haskell/haskell-src-exts/default.nix
+++ b/pkgs/development/libraries/haskell/haskell-src-exts/default.nix
@@ -12,6 +12,7 @@ cabal.mkDerivation (self: {
   ];
   buildTools = [ happy ];
   doCheck = false;
+  preConfigure = "runhaskell Setup.hs clean";
   meta = {
     homepage = "https://github.com/haskell-suite/haskell-src-exts";
     description = "Manipulating Haskell source: abstract syntax, lexer, parser, and pretty-printer";