From 67312f83ad8171579e25772e577c81b3fb8abdb9 Mon Sep 17 00:00:00 2001
From: Peter Simons <simons@cryp.to>
Date: Tue, 13 Jan 2015 21:34:23 +0100
Subject: [PATCH] haskell-generic-builder: pass "--with-gcc=$CC" on Darwin to
 help Cabal find Clang

Suggested in https://github.com/NixOS/nixpkgs/pull/5746.
---
 pkgs/development/haskell-modules/generic-builder.nix | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pkgs/development/haskell-modules/generic-builder.nix b/pkgs/development/haskell-modules/generic-builder.nix
index 0d535b27341..f8cca65aeb6 100644
--- a/pkgs/development/haskell-modules/generic-builder.nix
+++ b/pkgs/development/haskell-modules/generic-builder.nix
@@ -117,6 +117,8 @@ stdenv.mkDerivation ({
     ${optionalString (versionOlder "7.8" ghc.version && !isLibrary) ''
       configureFlags+=" --ghc-option=-j$NIX_BUILD_CORES"
       setupCompileFlags="-j$NIX_BUILD_CORES"
+    ''}${optionalString stdenv.isDarwin ''
+      configureFlags+=" --with-gcc=$CC"  # Cabal won't find clang without help.
     ''}
 
     packageConfDir="$TMP/package.conf.d"