diff --git a/pkgs/by-name/bu/butler/package.nix b/pkgs/by-name/bu/butler/package.nix
index 53a2886aca52..946c59b51749 100644
--- a/pkgs/by-name/bu/butler/package.nix
+++ b/pkgs/by-name/bu/butler/package.nix
@@ -32,6 +32,9 @@ buildGoModule rec {
 
   vendorHash = "sha256-A6u7bKI7eoptkjBuXoQlLYHkEVtrl8aNnBb65k1bFno=";
 
+  # Needed due to vendored dependencies breaking in gnu23 mode.
+  env.NIX_CFLAGS_COMPILE = "-std=gnu17";
+
   meta = {
     description = "Command-line itch.io helper";
     changelog = "https://github.com/itchio/butler/releases/tag/v${version}/CHANGELOG.md";