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/development/libraries/libevent/default.nix

@@ -0,0 +1,67 @@
+{ lib, stdenv, fetchurl, findutils, fixDarwinDylibNames
+, sslSupport? true, openssl
+}:
+
+assert sslSupport -> openssl != null;
+
+stdenv.mkDerivation rec {
+  pname = "libevent";
+  version = "2.1.12";
+
+  src = fetchurl {
+    url = "https://github.com/libevent/libevent/releases/download/release-${version}-stable/libevent-${version}-stable.tar.gz";
+    sha256 = "1fq30imk8zd26x8066di3kpc5zyfc5z6frr3zll685zcx4dxxrlj";
+  };
+
+  preConfigure = lib.optionalString (lib.versionAtLeast stdenv.hostPlatform.darwinMinVersion "11") ''
+    MACOSX_DEPLOYMENT_TARGET=10.16
+  '';
+
+  # libevent_openssl is moved into its own output, so that openssl isn't present
+  # in the default closure.
+  outputs = [ "out" "dev" ]
+    ++ lib.optional sslSupport "openssl"
+    ;
+  outputBin = "dev";
+  propagatedBuildOutputs = [ "out" ]
+    ++ lib.optional sslSupport "openssl"
+    ;
+
+  nativeBuildInputs = []
+    ++ lib.optional stdenv.hostPlatform.isDarwin fixDarwinDylibNames
+    ;
+
+  buildInputs = []
+    ++ lib.optional sslSupport openssl
+    ++ lib.optional stdenv.isCygwin findutils
+    ;
+
+  doCheck = false; # needs the net
+
+  postInstall = lib.optionalString sslSupport ''
+    moveToOutput "lib/libevent_openssl*" "$openssl"
+    substituteInPlace "$dev/lib/pkgconfig/libevent_openssl.pc" \
+      --replace "$out" "$openssl"
+    sed "/^libdir=/s|$out|$openssl|" -i "$openssl"/lib/libevent_openssl.la
+  '';
+
+  enableParallelBuilding = true;
+
+  meta = with lib; {
+    description = "Event notification library";
+    longDescription = ''
+      The libevent API provides a mechanism to execute a callback function
+      when a specific event occurs on a file descriptor or after a timeout
+      has been reached.  Furthermore, libevent also support callbacks due
+      to signals or regular timeouts.
+
+      libevent is meant to replace the event loop found in event driven
+      network servers.  An application just needs to call event_dispatch()
+      and then add or remove events dynamically without having to change
+      the event loop.
+    '';
+    homepage = "https://libevent.org/";
+    license = licenses.bsd3;
+    platforms = platforms.all;
+  };
+}