john: build with python3

pkgs/tools/security/john/default.nix

@@ -1,5 +1,5 @@
 { stdenv, fetchurl, openssl, nss, nspr, kerberos, gmp, zlib, libpcap, re2
-, gcc, pythonPackages, perl, perlPackages, makeWrapper
+, gcc, python3Packages, perl, perlPackages, makeWrapper
 }:
 
 with stdenv.lib;
@@ -33,8 +33,9 @@ stdenv.mkDerivation rec {
   '';
   configureFlags = [ "--disable-native-macro" ];
 
-  buildInputs = [ openssl nss nspr kerberos gmp zlib libpcap re2 gcc pythonPackages.wrapPython perl makeWrapper ];
-  propagatedBuildInputs = (with pythonPackages; [ dpkt scapy lxml ]) ++ # For pcap2john.py
+  buildInputs = [ openssl nss nspr kerberos gmp zlib libpcap re2 ];
+  nativeBuildInputs = [ gcc python3Packages.wrapPython perl makeWrapper ];
+  propagatedBuildInputs = (with python3Packages; [ dpkt scapy lxml ]) ++ # For pcap2john.py
                           (with perlPackages; [ DigestMD4 DigestSHA1 GetoptLong # For pass_gen.pl
                                                 perlldap ]); # For sha-dump.pl
                           # TODO: Get dependencies for radius2john.pl and lion2john-alt.pl