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/text/mdbook-pdf/default.nix

@@ -0,0 +1,28 @@
+{ lib, stdenv, fetchCrate, rustPlatform, pkg-config, openssl, CoreServices }:
+
+rustPlatform.buildRustPackage rec {
+  pname = "mdbook-pdf";
+  version = "0.1.2";
+
+  src = fetchCrate {
+    inherit pname version;
+    sha256 = "1ibmn8x9kyfd058hsyah2ggyzpahzf2w2qjn6rs9qv8mr3bvc0pv";
+  };
+
+  cargoSha256 = "0k47a5yqnjjc599vgk39ijy6fm62rr8xarvz37g0c7fx9cljhihz";
+
+  nativeBuildInputs = [ pkg-config ];
+
+  buildInputs = [ openssl ]
+    ++ lib.optionals stdenv.isDarwin [ CoreServices ];
+
+  # No test.
+  doCheck = false;
+
+  meta = with lib; {
+    description = "A backend for mdBook written in Rust for generating PDF";
+    license = licenses.gpl3Plus;
+    maintainers = with maintainers; [ hollowman6 ];
+    homepage = "https://github.com/HollowMan6/mdbook-pdf";
+  };
+}