anchor.diff:  , cmake, libssh2, openssl, mysql, darwin, git, perl, pcre, gecode_3, curl
   , msgpack, qt59, libsodium, snappy, libossp_uuid, lxc, libpcap, xorg, gtk2, buildRubyGem
   , cairo, re2, rake, gobjectIntrospection, gdk_pixbuf, zeromq, graphicsmagick, libcxx, file
  +, libselinux ? null, libsepol ? null
   }@args:
   
   let
  
positive.code:   };
  
    gtk2 = attrs: {
      nativeBuildInputs = [ pkgconfig ];
      buildInputs = [ gtk2 pcre xorg.libpthreadstubs xorg.libXdmcp];
      # CFLAGS must be set for this gem to detect gdkkeysyms.h correctly
      CFLAGS = "-I${gtk2.dev}/include/gtk-2.0 -I/non-existent-path";
  
negative.code: 
    gio2 = attrs: {
      nativeBuildInputs = [ pkgconfig ];
      buildInputs = [ gtk2 pcre gobjectIntrospection ] ++ lib.optionals stdenv.isLinux [ utillinux libselinux libsepol ];
    };
  
    gitlab-markup = attrs: { meta.priority = 1; };
  