incus.client: fix macOS builds

pkgs/by-name/in/incus/client.nix

@@ -30,6 +30,12 @@ buildGoModule {
   subPackages = [ "cmd/incus" ];
 
   postInstall = ''
+    # Needed for builds on systems with auto-allocate-uids to pass.
+    # Incus tries to read ~/.config/incus while generating completions
+    # to resolve user aliases.
+    export HOME="$(mktemp -d)"
+    mkdir -p "$HOME/.config/incus"
+
     installShellCompletion --cmd incus \
       --bash <($out/bin/incus completion bash) \
       --fish <($out/bin/incus completion fish) \