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/networking/libcoap/default.nix

@@ -0,0 +1,33 @@
+{ fetchFromGitHub, automake, autoconf, which, pkg-config, libtool, lib, stdenv, gnutls, asciidoc, doxygen
+, withTLS ? true
+, withDocs ? true
+}:
+stdenv.mkDerivation rec {
+  pname = "libcoap";
+  version = "4.3.0";
+  src = fetchFromGitHub {
+    repo = "libcoap";
+    owner = "obgm";
+    rev = "v${version}";
+    fetchSubmodules = true;
+    sha256 = "1l031ys833gch600g9g3lvbsr4nysx6glbbj4lwvx3ywl0jr6l9k";
+  };
+  nativeBuildInputs = [
+    automake
+    autoconf
+    which
+    libtool
+    pkg-config
+  ] ++ lib.optional withTLS gnutls ++ lib.optionals withDocs [ doxygen asciidoc ] ;
+  preConfigure = "./autogen.sh";
+  configureFlags = [ "--disable-shared" ]
+    ++ lib.optional (!withDocs) "--disable-documentation"
+    ++ lib.optional withTLS "--enable-dtls";
+  meta = with lib; {
+    homepage = "https://github.com/obgm/libcoap";
+    description = "A CoAP (RFC 7252) implementation in C";
+    platforms = platforms.unix;
+    license = licenses.bsd2;
+    maintainers = [ maintainers.kmein ];
+  };
+}