From a7dd5ca90f1ffbee6033bc4d65e9d43e9a956bb4 Mon Sep 17 00:00:00 2001
From: Alyssa Ross <hi@alyssa.is>
Date: Fri, 30 Apr 2021 12:23:00 +0000
Subject: [PATCH] systemd: fix build

---
 pkgs/os-specific/linux/systemd/default.nix | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/pkgs/os-specific/linux/systemd/default.nix b/pkgs/os-specific/linux/systemd/default.nix
index bd7c646c9200..1971f6ad1c68 100644
--- a/pkgs/os-specific/linux/systemd/default.nix
+++ b/pkgs/os-specific/linux/systemd/default.nix
@@ -151,6 +151,12 @@ stdenv.mkDerivation {
     ./0017-path-util.h-add-placeholder-for-DEFAULT_PATH_NORMAL.patch
     ./0018-logind-seat-debus-show-CanMultiSession-again.patch
     ./0019-pkg-config-derive-prefix-from-prefix.patch
+
+    # Fix -Werror=format.
+    (fetchpatch {
+      url = "https://github.com/systemd/systemd/commit/ab1aa6368a883bce88e3162fee2bea14aacedf23.patch";
+      sha256 = "1b280l5jrjsg8qhsang199mpqjhkpix4c8bm3blknjnq9iv43add";
+    })
   ];
 
   postPatch = ''