anchor.diff: -{ stdenv, ninja, which
  -
  -# default dependencies
  -, atk, bzip2, flac, speex, opus
  -, libevent, expat, libjpeg, snappy
  -, libpng, libxml2, libxslt, libcap
  -, xdg-utils, yasm, libwebp
  -, libusb, pciutils, nss
  -
  -, python, pythonPackages, perl, pkgconfig
  -, nspr, systemd_lib, kerberos
  -, util-linux_full, alsa-lib, cairo
  -, bison, gperf, fontconfig, libffi
  -, glib, gtk_2, dbus-glib, pango
  -, xorg, dbus, mesa, freetype
  -, protobuf-cpp, speechd, cups
  +{ stdenv
  +, bison
  +, gperf
  +, ninja
  +, perl
  +, pkgconfig
  +, python
  +, pythonPackages
  +, which
  +, yasm
  +
  +, alsa-lib
  +, atk
  +, bzip2
  +, cairo
  +, cups
  +, dbus
  +, dbus-glib
  +, expat
  +, flac
  +, fontconfig
  +, freetype
  +, glib
  +, gtk_2
  +, kerberos
  +, libcap
  +, libevent
  +, libffi
  +, libjpeg
  +, libpng
  +, libusb
  +, libwebp
  +, libxml2
  +, libxslt
  +, mesa
  +, nspr
  +, nss
  +, opus
  +, pango
  +, pciutils
  +, protobuf-cpp
  +, snappy
  +, speechd
  +, speex
  +, systemd_lib
  +, util-linux_full
  +, xdg-utils
  +, xorg
   
   # optional dependencies
   , libgcrypt # gnomeSupport || cupsSupport
  
positive.code:         chrome/browser/ui/webui/engagement/site_engagement_ui.cc
      '';
  
      gypFlags = mkGypFlags (gypFlagsUseSystemLibs // {
        linux_use_bundled_binutils = false;
        linux_use_bundled_gold = false;
        linux_use_gold_flags = true;
  
        proprietary_codecs = false;
        use_sysroot = false;
        use_gnome_keyring = gnomeKeyringSupport;
        use_gconf = gnomeSupport;
  
negative.code:   mkGypFlags =
      let
        sanitize = value:
          if value == true then
            "1"
          else if value == false then
            "0"
          else
            "${value}";
        toFlag = key: value:
          "-D${key}=${sanitize value}";
      in attrs:
      concatStringsSep " " (attrValues (mapAttrs toFlag attrs));
  
    # build paths and release info
    packageName = extraAttrs.packageName or extraAttrs.name;
  