anchor.diff:  , python-setup-hook
   # For the Python package set
   , packageOverrides ? (self: super: {})
  +, buildPackages
   }:
   
   assert x11Support -> tcl != null
  
positive.code:     # We rebuild three times, once for each optimization level
      # Python 3.7 implements PEP 552, introducing support for deterministic bytecode.
      # This is automatically used when `SOURCE_DATE_EPOCH` is set.
      find $out -name "*.py" | $out/bin/python     -m compileall -q -f -x "lib2to3" -i -
      find $out -name "*.py" | $out/bin/python -O  -m compileall -q -f -x "lib2to3" -i -
      find $out -name "*.py" | $out/bin/python -OO -m compileall -q -f -x "lib2to3" -i -
    '';
  
    passthru = let
  
negative.code:     "--with-system-expat"
      "--with-system-ffi"
      "--with-openssl=${openssl.dev}"
    ] ++ optionals (stdenv.hostPlatform != stdenv.buildPlatform) [
      "ac_cv_buggy_getaddrinfo=no"
      # Assume little-endian IEEE 754 floating point when cross compiling
      "ac_cv_little_endian_double=yes"
      "ac_cv_big_endian_double=no"
      "ac_cv_mixed_endian_double=no"
      "ac_cv_x87_double_rounding=yes"
      "ac_cv_tanh_preserves_zero_sign=yes"
      # Generally assume that things are present and work
      "ac_cv_posix_semaphores_enabled=yes"
      "ac_cv_broken_sem_getvalue=no"
      "ac_cv_wchar_t_signed=yes"
      "ac_cv_rshift_extends_sign=yes"
      "ac_cv_broken_nice=no"
      "ac_cv_broken_poll=no"
      "ac_cv_working_tzset=yes"
      "ac_cv_have_long_long_format=yes"
      "ac_cv_have_size_t_format=yes"
      "ac_cv_computed_gotos=yes"
      "ac_cv_file__dev_ptmx=yes"
      "ac_cv_file__dev_ptc=yes"
    ];
  
    preConfigure = ''
  