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/servers/mail/postgrey/default.nix

@@ -0,0 +1,34 @@
+{ fetchurl, perlPackages, lib, runCommand, postfix }:
+
+let
+    mk-perl-flags = inputs: lib.concatStringsSep " " (map (dep: "-I ${dep}/${perlPackages.perl.libPrefix}") inputs);
+    postgrey-flags = mk-perl-flags (with perlPackages; [
+      NetServer BerkeleyDB DigestSHA1 NetAddrIP IOMultiplex
+    ]);
+    policy-test-flags = mk-perl-flags (with perlPackages; [
+      ParseSyslog
+    ]);
+    version = "1.37";
+    name = "postgrey-${version}";
+in runCommand name {
+  src = fetchurl {
+    url = "https://postgrey.schweikert.ch/pub/${name}.tar.gz";
+    sha256 = "1xx51xih4711vrvc6d57il9ccallbljj5zhgqdb07jzmz11rakgz";
+  };
+  meta = with lib; {
+    description = "A postfix policy server to provide greylisting";
+    homepage = "https://postgrey.schweikert.ch/";
+    platforms = postfix.meta.platforms;
+    license = licenses.gpl2;
+  };
+} ''
+    mkdir -p $out/bin
+    cd $out
+    tar -xzf $src --strip-components=1
+    mv postgrey policy-test bin
+    sed -i -e "s,#!/usr/bin/perl -T,#!${perlPackages.perl}/bin/perl -T ${postgrey-flags}," \
+           -e "s#/etc/postfix#$out#" \
+        bin/postgrey
+    sed -i -e "s,#!/usr/bin/perl,#!${perlPackages.perl}/bin/perl ${policy-test-flags}," \
+        bin/policy-test
+''