From 5f00108cb4b6d85dc158718c9ec323313ad8663a Mon Sep 17 00:00:00 2001
From: Thierry Delafontaine <delafthi@pm.me>
Date: Fri, 4 Sep 2026 17:28:56 +0200
Subject: [PATCH] gavin-bc: recreate the `dc` link with the default umask 022

Upstream's `safe-install.sh` sets umask 077 before creating the `dc`
-> `bc` symlink. Darwin records symlink permissions, making the linkk
unreadable for non-root. This recreates the link with the default umask
022.

Resolves #555720
---
 pkgs/by-name/ga/gavin-bc/package.nix | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/pkgs/by-name/ga/gavin-bc/package.nix b/pkgs/by-name/ga/gavin-bc/package.nix
index 60ff410d8873..f70ba4ff5973 100644
--- a/pkgs/by-name/ga/gavin-bc/package.nix
+++ b/pkgs/by-name/ga/gavin-bc/package.nix
@@ -19,6 +19,13 @@ stdenv.mkDerivation (finalAttrs: {
     hash = "sha256-bIQk0HzUzL1Ju4+iDpFj1n+GKCj9a3AUAbYA3yX5TNg=";
   };
 
+  # Upstream's safe-install.sh sets umask 077 before creating the dc -> bc
+  # symlink. Darwin records symlink permissions, making the link unreadable for
+  # non-root. This recreates the link with the default umask 022.
+  postInstall = ''
+    ln -sf bc $out/bin/dc
+  '';
+
   nativeInstallCheckInputs = [ versionCheckHook ];
   versionCheckProgram = "${placeholder "out"}/bin/bc";
   doInstallCheck = true;