mkp224o: enable build on darwin

pkgs/tools/security/mkp224o/default.nix

@@ -20,7 +20,7 @@ stdenv.mkDerivation rec {
         { suffix = "donna";         configureFlags = ["--enable-donna"]; }
       ] ++ lib.optionals stdenv.hostPlatform.isx86 [
         { suffix = "donna-sse2";    configureFlags = ["--enable-donna-sse2"]; }
-      ] ++ lib.optionals stdenv.isx86_64 [
+      ] ++ lib.optionals (!stdenv.isDarwin && stdenv.isx86_64) [
         { suffix = "amd64-51-30k";  configureFlags = ["--enable-amd64-51-30k"]; }
         { suffix = "amd64-64-20k";  configureFlags = ["--enable-amd64-64-24k"]; }
       ];
@@ -41,7 +41,7 @@ stdenv.mkDerivation rec {
     description = "Vanity address generator for tor onion v3 (ed25519) hidden services";
     homepage = "http://cathug2kyi4ilneggumrenayhuhsvrgn6qv2y47bgeet42iivkpynqad.onion/";
     license = licenses.cc0;
-    platforms = platforms.linux;
+    platforms = platforms.unix;
     maintainers = with maintainers; [ volth ];
   };
 }