namd: build on aarch64. (#16639)
namd: build on aarch64. (#16639)


LLNL/spack,LLNL/spack,LLNL/spack,LLNL/spack,iulian787/spack,LLNL/spack,iulian787/spack,iulian787/spack,iulian787/spack,iulian787/spack