Fix jlink

externals/packages/avarice/default.nix

@@ -0,0 +1,24 @@
+{ lib, stdenv, fetchurl, perl, libbfd, libusb-compat-0_1, hidapi }:
+
+stdenv.mkDerivation rec {
+  pname = "avarice";
+  version = "2.14";
+  src = fetchurl {
+    url = "mirror://sourceforge/project/avarice/avarice/avarice-${version}/avarice-${version}.tar.bz2";
+    sha256 = "1ab2pxnkbw501iv1i9z9nj7hfzz4y7hid4l4q58cifm3aw17skjb";
+  };
+
+  nativeBuildInputs = [ perl ];
+  buildInputs = [ libbfd libusb-compat-0_1 hidapi ];
+  prePatch = ''
+    find src -type f -name '*.cc' -exec sed -i "s@ __unused@@g" {} \;
+  '';
+
+  meta = with lib; {
+    homepage = "http://avarice.sourceforge.net/";
+    description = "A program to facilitate AVR debugging using an Atmel or AVR ICE";
+    license = licenses.gpl2;
+    platforms = platforms.unix;
+    maintainers = [ maintainers.artemist ];
+  };
+}

sets/hardware.nix

@@ -1,7 +1,7 @@
 { config, pkgs, ... }:
 let
-  oldpkgs = import (fetchTarball "http://nixos.org/channels/nixos-20.03/nixexprs.tar.xz") { config.allowUnfree = true; };
-  jlink = oldpkgs.callPackage ../externals/packages/jlink { };
+  call = if (pkgs.targetPlatform.system == "x86_64-linux") then pkgs.pkgsi686Linux.callPackage else pkgs.callPackage;
+  jlink = call ../externals/packages/jlink { };
 in
 {
   services.udev.packages = [