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/tools/networking/kea/default.nix

@@ -0,0 +1,71 @@
+{ stdenv
+, lib
+, fetchurl
+, autoreconfHook
+, pkg-config
+, boost
+, botan2
+, libmysqlclient
+, log4cplus
+, postgresql
+, python3
+, nixosTests
+}:
+
+stdenv.mkDerivation rec {
+  pname = "kea";
+  version = "2.0.2"; # only even minor versions are stable
+
+  src = fetchurl {
+    url = "https://ftp.isc.org/isc/${pname}/${version}/${pname}-${version}.tar.gz";
+    sha256 = "sha256-jSghO9yOK7hwo4OzCsHlPVTh66Q9L4blFRsItmqmzzI=";
+  };
+
+  patches = [ ./dont-create-var.patch ];
+
+  postPatch = ''
+    substituteInPlace ./src/bin/keactrl/Makefile.am --replace '@sysconfdir@' "$out/etc"
+  '';
+
+  configureFlags = [
+    "--enable-perfdhcp"
+    "--enable-shell"
+    "--localstatedir=/var"
+    "--with-mysql=${lib.getDev libmysqlclient}/bin/mysql_config"
+    "--with-pgsql=${postgresql}/bin/pg_config"
+  ];
+
+  nativeBuildInputs = [
+    autoreconfHook
+    pkg-config
+  ];
+
+  buildInputs = [
+    boost
+    botan2
+    libmysqlclient
+    log4cplus
+    python3
+  ];
+
+  enableParallelBuilding = true;
+
+  passthru.tests = {
+    inherit (nixosTests) kea;
+  };
+
+  meta = with lib; {
+    homepage = "https://kea.isc.org/";
+    description = "High-performance, extensible DHCP server by ISC";
+    longDescription = ''
+      Kea is a new open source DHCPv4/DHCPv6 server being developed by
+      Internet Systems Consortium. The objective of this project is to
+      provide a very high-performance, extensible DHCP server engine for
+      use by enterprises and service providers, either as is or with
+      extensions and modifications.
+    '';
+    license = licenses.mpl20;
+    platforms = platforms.unix;
+    maintainers = with maintainers; [ fpletz hexa ];
+  };
+}