anchor.diff:  { stdenv, fetchurl, fetchpatch, gfortran, perl, libnl
   , rdma-core, zlib, numactl, libevent, hwloc, pkgsTargetTarget, symlinkJoin
  +, libpsm2, libfabric
   
   # Enable CUDA support
   , cudaSupport ? false, cudatoolkit ? null
  
positive.code:     ++ lib.optionals isLinux [ libnl numactl ]
      ++ lib.optionals cudaSupport [ cudatoolkit ]
      ++ [ libevent hwloc ]
      ++ lib.optional (isLinux || isFreeBSD) rdma-core;
  
    nativeBuildInputs = [ perl ];
  
  
negative.code:     # https://github.com/openucx/ucx
      # https://www.open-mpi.org/faq/?category=buildcuda
      ++ lib.optionals cudaSupport [ "--with-cuda=${cudatoolkit_joined}" "--enable-dlopen" ]
      ++ lib.optionals fabricSupport [ "--with-psm2=${libpsm2}" "--with-libfabric=${libfabric}" ]
      ;
  
    enableParallelBuilding = true;
  