uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

pkgs/servers/rippled/validator-keys-tool.nix

@@ -0,0 +1,36 @@
+{ stdenv, lib, fetchFromGitHub, cmake, openssl, boost, zlib, icu, rippled }:
+
+stdenv.mkDerivation rec {
+  pname = "rippled-validator-keys-tool";
+  version = "0.3.2";
+
+  src = fetchFromGitHub {
+    owner = "ripple";
+    repo = "validator-keys-tool";
+    rev = "5d7efcfeda3bdf6f5dda78056004a7c326321e9b";
+    sha256 = "1irm8asp6plk9xw3ksf4fqnim8h0vj3h96w638lx71pga1h4zvmy";
+  };
+
+  nativeBuildInputs = [ cmake ];
+  buildInputs = [ openssl boost zlib icu rippled ];
+
+  hardeningDisable = ["format"];
+
+  cmakeFlags = [
+    "-Dep_procs=1"
+  ];
+
+  installPhase = ''
+    runHook preInstall
+    install -D validator-keys $out/bin/validator-keys
+    runHook postInstall
+  '';
+
+  meta = with lib; {
+    description = "Generate master and ephemeral rippled validator keys";
+    homepage = "https://github.com/ripple/validator-keys-tool";
+    maintainers = with maintainers; [ offline rmcgibbo ];
+    license = licenses.isc;
+    platforms = [ "x86_64-linux" ];
+  };
+}