mdk3-master: modernize

pkgs/by-name/md/mdk3-master/package.nix

···
   wirelesstools,
 }:
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation (finalAttrs: {
   pname = "mdk3-master";
   version = "6-unstable-2015-05-24";
 
···
     runHook postInstall
   '';
 
-  meta = with lib; {
+  meta = {
     description = "MDK3 fork able to force reboot Access Points";
     homepage = "https://github.com/charlesxsh/mdk3-master";
-    changelog = "https://github.com/charlesxsh/mdk3-master/blob/${src.rev}/CHANGELOG";
-    license = licenses.gpl2Only;
-    maintainers = with maintainers; [ pinpox ];
+    changelog = "https://github.com/charlesxsh/mdk3-master/blob/${finalAttrs.src.rev}/CHANGELOG";
+    license = lib.licenses.gpl2Only;
+    maintainers = with lib.maintainers; [ pinpox ];
     mainProgram = "mdk3";
-    platforms = platforms.all;
+    platforms = lib.platforms.all;
   };
-}
+})