From 6454fb1bc0b5884d0c11c98a8a99735ef5a0cae8 Mon Sep 17 00:00:00 2001
From: Randy Eckenrode <randy@largeandhighquality.com>
Date: Fri, 14 Jul 2023 00:33:51 -0600
Subject: [PATCH] haskell.compiler.ghc962: fix build on Darwin after stdenv
 rework merge
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The switch to cctools-llvm made several LLVM tools the default on
Darwin, which includes llvm-ar. GHC will try to use `-L` with `ar` when
it is `llvm-ar`, but that doesn’t work currently on Darwin.

See https://gitlab.haskell.org/ghc/ghc/-/issues/23188.
---
 pkgs/development/compilers/ghc/common-hadrian.nix | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/pkgs/development/compilers/ghc/common-hadrian.nix b/pkgs/development/compilers/ghc/common-hadrian.nix
index b90a4934fdba..099a7fd2568f 100644
--- a/pkgs/development/compilers/ghc/common-hadrian.nix
+++ b/pkgs/development/compilers/ghc/common-hadrian.nix
@@ -385,6 +385,12 @@ stdenv.mkDerivation ({
     "--enable-dwarf-unwind"
     "--with-libdw-includes=${lib.getDev elfutils}/include"
     "--with-libdw-libraries=${lib.getLib elfutils}/lib"
+  ] ++ lib.optionals targetPlatform.isDarwin [
+    # Darwin uses llvm-ar. GHC will try to use `-L` with `ar` when it is `llvm-ar`
+    # but it doesn’t currently work because Cabal never uses `-L` on Darwin. See:
+    # https://gitlab.haskell.org/ghc/ghc/-/issues/23188
+    # https://github.com/haskell/cabal/issues/8882
+    "fp_cv_prog_ar_supports_dash_l=no"
   ];
 
   # Make sure we never relax`$PATH` and hooks support for compatibility.