From 3a4ab517310688c4696aa016714fc2eb48adfe00 Mon Sep 17 00:00:00 2001
From: Infinidoge <infinidoge@inx.moe>
Date: Mon, 22 May 2023 01:39:46 -0400
Subject: [PATCH] pkgs: add substituteSubset

---
 pkgs/default.nix           |  2 ++
 pkgs/substitute-subset.nix | 27 +++++++++++++++++++++++++++
 2 files changed, 29 insertions(+)
 create mode 100644 pkgs/substitute-subset.nix

diff --git a/pkgs/default.nix b/pkgs/default.nix
index e577f3c..d07e6f7 100644
--- a/pkgs/default.nix
+++ b/pkgs/default.nix
@@ -14,4 +14,6 @@ final: prev: {
   sim65 = final.callPackage ./sim65.nix { };
 
   unbted = final.callPackage ./unbted.nix { };
+
+  substituteSubset = final.callPackage ./substitute-subset.nix { };
 }
diff --git a/pkgs/substitute-subset.nix b/pkgs/substitute-subset.nix
new file mode 100644
index 0000000..2edc1ee
--- /dev/null
+++ b/pkgs/substitute-subset.nix
@@ -0,0 +1,27 @@
+{ lib, stdenv }:
+
+args:
+
+stdenv.mkDerivation ({
+  name = if args ? name then args.name else baseNameOf (toString args.src);
+  builder = builtins.toFile "builder.sh" ''
+    source $stdenv/setup
+    set -o pipefail
+
+    eval "$preInstall"
+
+    args=
+
+    cp -r "$src" "$out"
+
+    pushd "$out"
+    echo -ne "${lib.concatStringsSep "\\0" args.files}" | xargs -0 -n1 -I {} -- find {} -type f -print0 | while read -d "" line; do
+      substituteAllInPlace "$line"
+    done
+    popd
+
+    eval "$postInstall"
+  '';
+  preferLocalBuild = true;
+  allowSubstitutes = false;
+} // args)