anchor.diff:    '';
   
     NIX_CFLAGS_COMPILE = "-I.";
  -  
  +
  +  buildFlags = "memtest.bin";
  +
     installPhase = ''
       mkdir -p $out
       cp memtest.bin $out/
  
positive.code: { stdenv, fetchurl }:
  
  stdenv.mkDerivation {
    name = "memtest86+-4.20";
    
    src = fetchurl {
      url = http://www.memtest.org/download/4.20/memtest86+-4.20.tar.gz;
      sha256 = "0dw7kvfxiwqdmhapbz6ds1j9fralbky56hnzj4c6fsqfinbwwc2n";
    };
  
    preBuild = ''
  
negative.code: 
    meta = {
      homepage = http://www.memtest.org/;
      description = "A tool to detect memory errors";
      license = stdenv.lib.licenses.gpl2;
    };
  }
  