pixiecore: expand platforms to unix

pkgs/tools/networking/pixiecore/default.nix

@@ -23,6 +23,6 @@ buildGoModule rec {
     homepage = "https://github.com/danderson/netboot/tree/master/pixiecore";
     license =  lib.licenses.asl20;
     maintainers = with lib.maintainers; [ bbigras danderson ];
-    platforms = lib.platforms.linux;
+    platforms = lib.platforms.unix;
   };
 }