anchor.diff:      owner = "Sandia-OpenSHMEM";
       repo = "SOS";
       rev = "v${version}";
  -    sha256 = "042zhdi2jr08jaliilkx7gmhhdlrwikkq667d2iki8q553klrn1k";
  +    sha256 = "0wj3ijxawpy5i33j7lnrlk4h6fhww0n3cwjfk28fpnxz30spcfwk";
     };
   
     configureFlags = [
  
positive.code:     "--with-ofi=${libfabric}"
    ];
  
    nativeBuildInputs = [ autoconf automake libtool openmpi openssh ];
    buildInputs = [ rdma-core libfabric libnl perl ];
  
    enableParallelBuilding = true;
  
negative.code: { stdenv, fetchFromGitHub, autoconf, automake, libtool
  , rdma-core, libfabric, libnl, perl, mpi, openssh
  } :
  
  let
    version = "1.5.0";
  
  in stdenv.mkDerivation {
    name = "sos-${version}";
  