From eaa3b1d4d5095a8821a0969981c4f029c52435fe Mon Sep 17 00:00:00 2001
From: Alexis Hildebrandt <afh@surryhill.net>
Date: Sun, 31 May 2026 10:32:45 +0200
Subject: [PATCH] dateutils: fix build errors

---
 pkgs/by-name/da/dateutils/package.nix | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/pkgs/by-name/da/dateutils/package.nix b/pkgs/by-name/da/dateutils/package.nix
index 41fac34b3d23..a73c984fe2e1 100644
--- a/pkgs/by-name/da/dateutils/package.nix
+++ b/pkgs/by-name/da/dateutils/package.nix
@@ -2,8 +2,11 @@
   lib,
   stdenv,
   fetchurl,
+  fetchpatch,
   autoreconfHook,
   tzdata,
+  bison,
+  flex,
 }:
 
 stdenv.mkDerivation (finalAttrs: {
@@ -12,20 +15,33 @@ stdenv.mkDerivation (finalAttrs: {
 
   src = fetchurl {
     url = "https://bitbucket.org/hroptatyr/dateutils/downloads/dateutils-${finalAttrs.version}.tar.xz";
-    sha256 = "sha256-uP6gsJcUu63yArmzQ0zOa1nCgueGkmjQwIuFiA/btEY=";
+    hash = "sha256-uP6gsJcUu63yArmzQ0zOa1nCgueGkmjQwIuFiA/btEY=";
   };
 
+  patches = [
+    # TODO: Remove when updating to the next release.
+    (fetchpatch {
+      url = "https://github.com/hroptatyr/dateutils/commit/b30902c2f46288b570c7fa8de06e17cc7dfd6a37.patch";
+      hash = "sha256-38LBUv4FLpK3TTIXXvIGr0qE0CSqF2IqCbZY5RGyi6Q=";
+    })
+  ];
+
   # https://github.com/hroptatyr/dateutils/issues/148
   postPatch = "rm test/dzone.008.ctst";
 
-  nativeBuildInputs = [ autoreconfHook ];
+  nativeBuildInputs = [
+    autoreconfHook
+    flex
+    bison
+  ];
   buildInputs = [ tzdata ]; # needed for datezone
+
   enableParallelBuilding = true;
 
   doCheck = true;
 
   meta = {
-    description = "Bunch of tools that revolve around fiddling with dates and times in the command line";
+    description = "Command-line utilities for date and time calculations and conversions";
     homepage = "http://www.fresse.org/dateutils/";
     license = lib.licenses.bsd3;
     platforms = lib.platforms.unix;