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/graphics/blockhash/default.nix

@@ -0,0 +1,30 @@
+{ lib, stdenv, fetchFromGitHub, python3, pkg-config, imagemagick, wafHook }:
+
+stdenv.mkDerivation rec {
+  pname = "blockhash";
+  version = "0.3.2";
+
+  src = fetchFromGitHub {
+    owner = "commonsmachinery";
+    repo = "blockhash";
+    rev = "v${version}";
+    sha256 = "0x3lvhnkb4c3pyq6p81qnnqimz35wpippiac506dgjx3b1848v35";
+  };
+
+  nativeBuildInputs = [ python3 pkg-config wafHook ];
+  buildInputs = [ imagemagick ];
+
+  strictDeps = true;
+
+  meta = with lib; {
+    homepage = "https://github.com/commonsmachinery/blockhash";
+    description = ''
+      This is a perceptual image hash calculation tool based on algorithm
+      descibed in Block Mean Value Based Image Perceptual Hashing by Bian Yang,
+      Fan Gu and Xiamu Niu.
+    '';
+    license = licenses.mit;
+    maintainers = [ maintainers.infinisil ];
+    platforms = platforms.unix;
+  };
+}