From 4eb49533cbbab3994b0819de966501d994e8b688 Mon Sep 17 00:00:00 2001
From: Will Fancher <elvishjerricco@gmail.com>
Date: Thu, 17 May 2018 05:27:38 -0400
Subject: [PATCH] Work around GHCJS bug with ghcjs-boot -j1

---
 pkgs/development/compilers/ghcjs-ng/default.nix | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pkgs/development/compilers/ghcjs-ng/default.nix b/pkgs/development/compilers/ghcjs-ng/default.nix
index 785f5b878f7..035687a64f3 100644
--- a/pkgs/development/compilers/ghcjs-ng/default.nix
+++ b/pkgs/development/compilers/ghcjs-ng/default.nix
@@ -77,10 +77,12 @@ in stdenv.mkDerivation {
       wrapProgram $out/bin/haddock-ghcjs --add-flags "-B$out/libexec"
       wrapProgram $out/bin/ghcjs-pkg --add-flags "--global-package-db=$out/libexec/package.conf.d"
 
-      env PATH=$out/bin:$PATH $out/bin/ghcjs-boot -j $NIX_BUILD_CORES --with-ghcjs-bin $out/bin
+      env PATH=$out/bin:$PATH $out/bin/ghcjs-boot -j1 --with-ghcjs-bin $out/bin
     '';
 
-    enableParallelBuilding = true;
+    # We hard code -j1 as a temporary workaround for
+    # https://github.com/ghcjs/ghcjs/issues/654
+    # enableParallelBuilding = true;
 
     inherit passthru;