From 51856742bb781f1c5719fcb4717cc6aeb3874997 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sat, 17 Aug 2019 18:19:49 +0200
Subject: [PATCH] Fix fully static build.

See https://github.com/nh2/static-haskell-nix/issues/47.

The file was first updated to the latest one from
https://github.com/nh2/static-haskell-nix/blob/761f34bb/static-stack2nix-builder-example/default.nix
and then the linker flags were added.
---
 default.nix | 39 ++++++++++++++++++++++++++++++++-------
 1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/default.nix b/default.nix
index fed3572..99f7992 100644
--- a/default.nix
+++ b/default.nix
@@ -4,17 +4,24 @@
 # also the following might be needed:
 # sysctl kernel.unprivileged_userns_clone=1
 {
-    stack2nix-output-path ? "custom-stack2nix-output.nix",
+  stack2nix-output-path ? "custom-stack2nix-output.nix",
 }:
 let
   cabalPackageName = "geval";
   compiler = "ghc844"; # matching stack.yaml
 
-  # Pin nixpkgs version.
-  pkgs = import (fetchTarball https://github.com/nh2/nixpkgs/archive/a2d7e9b875e8ba7fd15b989cf2d80be4e183dc72.tar.gz) {};
-
   # Pin static-haskell-nix version.
-  static-haskell-nix = fetchTarball https://github.com/nh2/static-haskell-nix/archive/1d37d9a83e570eceef9c7dad5c89557f8179a076.tar.gz;
+  static-haskell-nix =
+    if builtins.pathExists ../.in-static-haskell-nix
+      then toString ../. # for the case that we're in static-haskell-nix itself, so that CI always builds the latest version.
+      # Update this hash to use a different `static-haskell-nix` version:
+      else fetchTarball https://github.com/nh2/static-haskell-nix/archive/c49fbe730c49730d9568a9fec36f25f4580739f2.tar.gz;
+
+  # Pin nixpkgs version
+  # By default to the one `static-haskell-nix` provides, but you may also give
+  # your own as long as it has the necessary patches, using e.g.
+  #     pkgs = import (fetchTarball https://github.com/nh2/nixpkgs/archive/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa123.tar.gz) {};
+  pkgs = import "${static-haskell-nix}/nixpkgs.nix";
 
   stack2nix-script = import "${static-haskell-nix}/static-stack2nix-builder/stack2nix-script.nix" {
     inherit pkgs;
@@ -28,19 +35,37 @@ let
     # disableOptimization = true; # for compile speed
   };
 
+  static_package = static-stack2nix-builder.static_package.overrideAttrs (old: {
+    # Hack on static libraries the package needs that are, for reasons not yet
+    # clear, not propagated automatically via the `cairo` Haskell library and
+    # its `pkgconfig-depends` flag.
+    # See https://github.com/nh2/static-haskell-nix/issues/47.
+    # It's annoying that we have to do this with NIX_LDFLAGS, which is the
+    # lowest-level hack via which one can insert linker flags, but we haven't
+    # found higher level entry points yet that work.
+    # Cabal's `--ld-options` might be one, but it doesn't work yet because
+    # of GHC not passing them on in the correct order:
+    # https://gitlab.haskell.org/ghc/ghc/issues/17071
+    preConfigure = ''
+     ${old.preConfigure or ""}
+     export NIX_LDFLAGS="-lcairo -lfontconfig -lfreetype -lpixman-1 -lexpat -lpng $NIX_LDFLAGS"
+   '';
+  });
+
   # Full invocation, including pinning `nix` version itself.
   fullBuildScript = pkgs.writeScript "stack2nix-and-build-script.sh" ''
     #!/usr/bin/env bash
     set -eu -o pipefail
     STACK2NIX_OUTPUT_PATH=$(${stack2nix-script})
+    export NIX_PATH=nixpkgs=${pkgs.path}
     ${pkgs.nix}/bin/nix-build --no-link -A static_package --argstr stack2nix-output-path "$STACK2NIX_OUTPUT_PATH" "$@"
   '';
 
 in
   {
-    static_package = static-stack2nix-builder.static_package;
+    inherit static_package;
     inherit fullBuildScript;
     # For debugging:
     inherit stack2nix-script;
     inherit static-stack2nix-builder;
-}
\ No newline at end of file
+  }