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/applications/accessibility/svkbd/default.nix

@@ -0,0 +1,59 @@
+{ lib
+, stdenv
+, fetchurl
+, writeText
+, pkg-config
+, libX11
+, libXft
+, libXi
+, libXinerama
+, libXtst
+, layout ? null
+, conf ? null
+, patches ? [ ]
+}:
+
+stdenv.mkDerivation rec {
+  pname = "svkbd";
+  version = "0.4.1";
+
+  src = fetchurl {
+    url = "https://dl.suckless.org/tools/svkbd-${version}.tar.gz";
+    sha256 = "sha256-+8Jh/D4dgULhRXtC1tZQg6AK4POh9czyRyrMi0auD1o=";
+  };
+
+  inherit patches;
+
+  postPatch = let
+    configFile = if lib.isDerivation conf || lib.isPath conf then
+      conf
+    else
+      writeText "config.def.h" conf;
+  in lib.optionalString (conf != null) ''
+    cp ${configFile} config.def.h
+  '';
+
+  nativeBuildInputs = [
+    pkg-config
+  ];
+
+  buildInputs = [
+    libX11
+    libXft
+    libXi
+    libXinerama
+    libXtst
+  ];
+
+  makeFlags = [
+    "PREFIX=${placeholder "out"}"
+  ] ++ lib.optional (layout != null) "LAYOUT=${layout}";
+
+  meta = with lib; {
+    description = "Simple virtual keyboard";
+    homepage = "https://tools.suckless.org/x/svkbd/";
+    license = licenses.mit;
+    platforms = platforms.linux;
+    maintainers = with maintainers; [ dotlambda ];
+  };
+}