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/build-support/dotnet/make-nuget-source/default.nix

@@ -0,0 +1,38 @@
+{ dotnetPackages, lib, xml2, stdenvNoCC }:
+
+{ name
+, description ? ""
+, deps ? []
+}:
+
+let
+  nuget-source = stdenvNoCC.mkDerivation rec {
+    inherit name;
+
+    meta.description = description;
+    nativeBuildInputs = [ dotnetPackages.Nuget xml2 ];
+
+    buildCommand = ''
+      export HOME=$(mktemp -d)
+      mkdir -p $out/{lib,share}
+
+      ${lib.concatMapStringsSep "\n" (dep: ''
+        nuget init "${dep}" "$out/lib"
+      '') deps}
+
+      # Generates a list of all licenses' spdx ids, if available.
+      # Note that this currently ignores any license provided in plain text (e.g. "LICENSE.txt")
+      find "$out/lib" -name "*.nuspec" -exec sh -c \
+        "NUSPEC=\$(xml2 < {}) && echo "\$NUSPEC" | grep license/@type=expression | tr -s \  '\n' | grep "license=" | cut -d'=' -f2" \
+      \; | sort -u > $out/share/licenses
+    '';
+  } // { # We need data from `$out` for `meta`, so we have to use overrides as to not hit infinite recursion.
+    meta.licence = let
+      depLicenses = lib.splitString "\n" (builtins.readFile "${nuget-source}/share/licenses");
+    in (lib.flatten (lib.forEach depLicenses (spdx:
+      if (spdx != "")
+        then lib.getLicenseFromSpdxId spdx
+        else []
+    )));
+  };
+in nuget-source