From 449fbec9be1865fca59e973f05dd06d213820c5e Mon Sep 17 00:00:00 2001
From: Will Dietz <w@wdtz.org>
Date: Mon, 25 Jun 2018 15:47:22 -0500
Subject: [PATCH 1/3] ghcHEAD: add musl and cross fixes recently applied to
 8.4.3 and 8.2.2

---
 pkgs/development/compilers/ghc/head.nix | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/compilers/ghc/head.nix b/pkgs/development/compilers/ghc/head.nix
index 8ccd72ef55a..ec9ff56c458 100644
--- a/pkgs/development/compilers/ghc/head.nix
+++ b/pkgs/development/compilers/ghc/head.nix
@@ -50,7 +50,8 @@ let
   '' + stdenv.lib.optionalString enableIntegerSimple ''
     INTEGER_LIBRARY = integer-simple
   '' + stdenv.lib.optionalString (targetPlatform != hostPlatform) ''
-    Stage1Only = YES
+    Stage1Only = ${if targetPlatform.system == hostPlatform.system then "NO" else "YES"}
+    CrossCompilePrefix = ${targetPrefix}
     HADDOCK_DOCS = NO
     BUILD_SPHINX_HTML = NO
     BUILD_SPHINX_PDF = NO

From 61e3bd20a04f9199744e9d0f38b3b7a5d442bdbd Mon Sep 17 00:00:00 2001
From: Will Dietz <w@wdtz.org>
Date: Mon, 25 Jun 2018 15:49:00 -0500
Subject: [PATCH 2/3] ghcHEAD: move hardeningDisable definition for cleaner
 diff against 8.4.3

NFCI (no functionality change intendend)
---
 pkgs/development/compilers/ghc/head.nix | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pkgs/development/compilers/ghc/head.nix b/pkgs/development/compilers/ghc/head.nix
index ec9ff56c458..a71b08cd39f 100644
--- a/pkgs/development/compilers/ghc/head.nix
+++ b/pkgs/development/compilers/ghc/head.nix
@@ -167,10 +167,10 @@ stdenv.mkDerivation rec {
   # that in turn causes GHCi to abort
   stripDebugFlags = [ "-S" ] ++ stdenv.lib.optional (!targetPlatform.isDarwin) "--keep-file-symbols";
 
-  hardeningDisable = [ "format" ];
-
   checkTarget = "test";
 
+  hardeningDisable = [ "format" ];
+
   postInstall = ''
     for bin in "$out"/lib/${name}/bin/*; do
       isELF "$bin" || continue

From 0e40e0cc7d4748c3a1c66e2b37f0d95b9ffc0772 Mon Sep 17 00:00:00 2001
From: Will Dietz <w@wdtz.org>
Date: Mon, 25 Jun 2018 15:49:32 -0500
Subject: [PATCH 3/3] ghcHEAD: useLLVM needed for musl here as well

---
 pkgs/development/compilers/ghc/head.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkgs/development/compilers/ghc/head.nix b/pkgs/development/compilers/ghc/head.nix
index a71b08cd39f..43e6473fc24 100644
--- a/pkgs/development/compilers/ghc/head.nix
+++ b/pkgs/development/compilers/ghc/head.nix
@@ -7,7 +7,7 @@
 
 , libffi, libiconv ? null, ncurses
 
-, useLLVM ? !targetPlatform.isx86
+, useLLVM ? !targetPlatform.isx86 || targetPlatform.isMusl
 , # LLVM is conceptually a run-time-only depedendency, but for
   # non-x86, we need LLVM to bootstrap later stages, so it becomes a
   # build-time dependency too.