Add support for ledger and trezor with bitcoin-core/HWI

pkgs/hwi/default.nix

@@ -0,0 +1,29 @@
+{ stdenv, fetchurl, fetchFromGitHub, python35 }:
+
+with stdenv.lib;
+with python35.pkgs;
+
+let
+  buildInputs = [ mnemonic ecdsa typing-extensions hidapi libusb1 pyaes ];
+in
+buildPythonPackage rec {
+  pname = "hwi";
+  version = "1.0.0";
+
+  src = fetchFromGitHub {
+    owner = "bitcoin-core";
+    repo = "HWI";
+    rev = "4dd56fda3cd9cade8abc482e43e7733ddc8360a9";
+    sha256 = "1xy2iq95b8a4cm9k5yzsi8lx1ha0dral3lhshbl1mfm1fi9ch3nk";
+  };
+
+  # TODO: enable tests
+  doCheck = false;
+
+  inherit buildInputs;
+  propagatedBuildInputs = buildInputs;
+
+  meta = with lib; {
+    homepage = https://github.com/bitcoin-core/hwi;
+  };
+}