Update doc

    > cd mfix

    > mkdir build

    > cd build

    > cmake [amrex options] -DCMAKE_BUILD_TYPE=[Debug|Release|RelWithDebInfo|MinSizeRel] ..

    > cmake [mfix options] [amrex options] -DCMAKE_BUILD_TYPE=[Debug|Release|RelWithDebInfo|MinSizeRel] ..

    > make -j

``[amrex options]`` in the snippet above is a list of any of the AMReX configuration options listed in the `AMReX user guide <https://amrex-codes.github.io/amrex/docs_html/BuildingAMReX.html#building-with-cmake>`_

``[amrex options]`` in the snippet above is a list of any of the AMReX configuration options listed in

the `AMReX user guide <https://amrex-codes.github.io/amrex/docs_html/BuildingAMReX.html#building-with-cmake>`_,

while ``[mfix options]`` is any of the configuration options listed :ref:`here <tab:mfixcmakeoptions>`.

For example, to enable AMReX profiling capabilities in MFiX_Exa, configure as follows:

.. code:: shell

    > cmake [mfix options] -DAMReX_TINY_PROFILE=yes -DCMAKE_BUILD_TYPE=[Debug|Release|RelWithDebInfo|MinSizeRel] ..

Working with the AMReX submodule

``/absolute/path/to/amrex/installdir`` before searching system paths

for an available AMReX installation.

``AMReX_ROOT`` can also be set as an environmental variable instead of passing it as a command line option.

``[mfix options]`` indicates any of the configuration option listed in the table below.

``[mfix options]`` indicates any of the configuration option listed in the table below.

.. _tab:mfixcmakeoptions:

.. table:: MFiX-Exa configuration options

           +-----------------+------------------------------+------------------+-------------+

           | Option name     | Description                  | Possible values  | Default     |