anchor.diff:  
   stdenv.mkDerivation rec {
     pname = "libpsm2";
  -  version = "11.2.156";
  -  ifs_version = "10_10_2_0_44";
  +  version = "11.2.185";
   
     preConfigure= ''
       export UDEVDIR=$out/etc/udev
  
positive.code: 
    buildInputs = [ numactl pkgconfig ];
  
    installFlags = [ 
      "DESTDIR=$(out)"
      "UDEVDIR=/etc/udev"
      "LIBPSM2_COMPAT_CONF_DIR=/etc"
  
negative.code:   src = fetchFromGitHub {
      owner = "intel";
      repo = "opa-psm2";
      rev = "PSM2_${version}";
      sha256 = "062hg4r6gz7pla9df70nqs5i2a3mp1wszmp4l0g771fykhhrxsjg";
    };
  
    postInstall = ''
  