anchor.diff:    inherit (stdenv.lib)
       concatStringsSep
       head
  -    optional
       optionals
       optionalString
       splitString
  
positive.code:     $out/bin/python${channel} -c "import lzma"
    '';
  
    postFixup = ''
      # The lines we are replacing dont include libpython so we parse it out
      LIBS_WITH_PYTHON="$(pkg-config --libs --static $out/lib/pkgconfig/python-${channel}.pc)"
      LIBS="$(echo "$LIBS_WITH_PYTHON" | sed 's,[ ]*\(-L\|-l\)[^ ]*python[^ ]*[ ]*, ,g')"
    '' + ''
      sed -i $out/lib/python${channel}/config${ifPy3 "-${channel}m" ""}/Makefile \
        -e "s@^LIBS=.*@LIBS= $LIBS@g"
  
      # We need to update _sysconfigdata.py{,o,c}
      sed -i "s@'\(SH\|\)LIBS': '.*',@'\1LIBS': '$LIBS',@g" $out/lib/python${channel}/_sysconfigdata.py
    '' + optionalString isPy2 ''
      rm $out/lib/python${channel}/_sysconfigdata.py{o,c}
    '' + optionalString isPy3 ''
      rm $out/lib/python${channel}/__pycache__/_sysconfigdata*.pyc
    '' + ''
      $out/bin/python${channel} -c "import _sysconfigdata"
      $out/bin/python${channel} -O -c "import _sysconfigdata"
      $out/bin/python${channel} -OO -c "import _sysconfigdata"
      $out/bin/python${channel} -OOO -c "import _sysconfigdata"
  
      sed --follow-symlinks -i $out/bin/python${channel}-config \
        -e "s@^LIBS=\".*\"@LIBS=\"$LIBS_WITH_PYTHON\"@g"
    '';
  
    # Used by python-2.7-deterministic-build.patch
    DETERMINISTIC_BUILD = 1;
  
negative.code:     (ifPy2 "--enable-unicode=ucs4" null)
      #(wtFlag "gcc" (!stdenv.cc.isClang) null)
      #"--enable-big-digits" # py3
      (wtFlag "pydebug" pydebug null)
      #"--with-hash-algorithm" # py3
      (if (versionAtLeast channel "3.5") then
        # Flag is not a boolean
  