From 80d39a273e313b0837fca382edbe92eaf85d031a Mon Sep 17 00:00:00 2001
From: Peter Simons <simons@cryp.to>
Date: Sun, 4 May 2014 13:37:15 +0200
Subject: [PATCH] HTTP-4000.2.13: patch Cabal file to declare FlexibleContexts
 extension to fix the build with ghc-head

https://github.com/haskell/HTTP/issues/62
---
 pkgs/development/libraries/haskell/HTTP/4000.2.13.nix | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pkgs/development/libraries/haskell/HTTP/4000.2.13.nix b/pkgs/development/libraries/haskell/HTTP/4000.2.13.nix
index 3a78e8f16744..9963b7e9770c 100644
--- a/pkgs/development/libraries/haskell/HTTP/4000.2.13.nix
+++ b/pkgs/development/libraries/haskell/HTTP/4000.2.13.nix
@@ -14,6 +14,9 @@ cabal.mkDerivation (self: {
   ];
   jailbreak = true;
   doCheck = false;
+  preConfigure = self.stdenv.lib.optional (self.stdenv.lib.versionOlder "7.9" self.ghc.version) ''
+    sed -i -e 's|Extensions: |Extensions: FlexibleContexts, |' HTTP.cabal
+  '';
   meta = {
     homepage = "https://github.com/haskell/HTTP";
     description = "A library for client-side HTTP";