From c865b8e35e364e1193770243bc4b41e8178b1982 Mon Sep 17 00:00:00 2001
From: Bas van Dijk <v.dijk.bas@gmail.com>
Date: Fri, 7 Apr 2017 01:28:44 +0200
Subject: [PATCH] haskell: add the linkWithGold function to link packages with
 ld.gold

Also support linking the double-conversion package with ld.gold.
---
 pkgs/development/haskell-modules/configuration-common.nix | 8 +++++++-
 pkgs/development/haskell-modules/lib.nix                  | 3 +++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/haskell-modules/configuration-common.nix b/pkgs/development/haskell-modules/configuration-common.nix
index d84db5279519..643f71f9f874 100644
--- a/pkgs/development/haskell-modules/configuration-common.nix
+++ b/pkgs/development/haskell-modules/configuration-common.nix
@@ -171,7 +171,13 @@ self: super: {
     else dontCheck super.fsnotify;
 
   double-conversion = if !pkgs.stdenv.isDarwin
-    then addExtraLibrary super.double-conversion pkgs.stdenv.cc.cc.lib
+    then addExtraLibrary
+           # https://github.com/bos/double-conversion/pull/17
+           (appendPatch super.double-conversion (pkgs.fetchpatch {
+              url = "https://github.com/basvandijk/double-conversion/commit/0927e347d53dbd96d1949930e728cc2471dd4b14.patch";
+              sha256 = "042yqbq5p6nc9nymmbz9hgp51dlc5asaj9bf91kw5fph6dw2hwg9";
+           }))
+           pkgs.stdenv.cc.cc.lib
     else addExtraLibrary (overrideCabal super.double-conversion (drv:
       {
         postPatch = ''
diff --git a/pkgs/development/haskell-modules/lib.nix b/pkgs/development/haskell-modules/lib.nix
index 912d26c806c7..f88f2f2cf54b 100644
--- a/pkgs/development/haskell-modules/lib.nix
+++ b/pkgs/development/haskell-modules/lib.nix
@@ -79,6 +79,9 @@ rec {
     fixupPhase = ":";
   });
 
+  linkWithGold = drv : appendConfigureFlag drv
+    "--ghc-option=-optl-fuse-ld=gold --ld-option=-fuse-ld=gold --with-ld=ld.gold";
+
   # link executables statically against haskell libs to reduce closure size
   justStaticExecutables = drv: overrideCabal drv (drv: {
     enableSharedExecutables = false;