From 3868cad8325ceffd4a6afe1037107043bc34c878 Mon Sep 17 00:00:00 2001
From: YPares <yves.pares@gmail.com>
Date: Wed, 15 Jun 2016 17:08:41 +0200
Subject: [PATCH] haskell: generic-stack-builder sets an env var

generic-stack-builder was not setting STACK_PLATFORM_VARIANT="nix".
This is required by stack when handling its haskell packages database
snapshot. Stack must keep separated packages built with its own GHC
and those built with GHC from Nixpkgs.
---
 pkgs/development/haskell-modules/generic-stack-builder.nix | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pkgs/development/haskell-modules/generic-stack-builder.nix b/pkgs/development/haskell-modules/generic-stack-builder.nix
index 07421b1d14f8..09bd38ccc933 100644
--- a/pkgs/development/haskell-modules/generic-stack-builder.nix
+++ b/pkgs/development/haskell-modules/generic-stack-builder.nix
@@ -16,6 +16,7 @@ stdenv.mkDerivation (args // {
     optional stdenv.isLinux glibcLocales ++
     [ ghc pkgconfig ];
 
+  STACK_PLATFORM_VARIANT="nix";
   STACK_IN_NIX_SHELL=1;
   STACK_IN_NIX_EXTRA_ARGS =
     concatMap (pkg: ["--extra-lib-dirs=${pkg}/lib"