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/science/electronics/kicad/libraries.nix

@@ -0,0 +1,30 @@
+{ lib, stdenv
+, cmake
+, gettext
+, libSrc
+}:
+let
+  mkLib = name:
+    stdenv.mkDerivation {
+      pname = "kicad-${name}";
+      version = builtins.substring 0 10 (libSrc name).rev;
+
+      src = libSrc name;
+
+      nativeBuildInputs = [ cmake ];
+
+      meta = rec {
+        license = lib.licenses.cc-by-sa-40;
+        platforms = lib.platforms.all;
+        # the 3d models are a ~1 GiB download and occupy ~5 GiB in store.
+        # this would exceed the hydra output limit
+        hydraPlatforms = if (name == "packages3d") then [ ] else platforms;
+      };
+    };
+in
+{
+  symbols = mkLib "symbols";
+  templates = mkLib "templates";
+  footprints = mkLib "footprints";
+  packages3d = mkLib "packages3d";
+}