Headercheck
-----------

Infrastructure for the optional ``headercheck`` validation target.

.. cmake:variable:: ENABLE_HEADERCHECK

  Enable the CMake reimplementation of the old autotools ``make headercheck``
  feature.

  The feature has historically been somewhat fragile, so it is disabled by
  default.

.. cmake:command:: setup_headercheck

  .. dune:internal::

  Collect the public header files of the current module and create the global
  ``headercheck`` target if it does not exist yet.

.. cmake:command:: exclude_from_headercheck

  .. dune:internal::

  Remove the given header files from the global headercheck list.

.. cmake:command:: exclude_dir_from_headercheck

  .. dune:internal::

  Remove all ``*.hh`` files in the current directory from the global
  headercheck list.

.. cmake:command:: exclude_subdir_from_headercheck

  .. dune:internal::

  Remove all ``*.hh`` files below the given subdirectory from the global
  headercheck list.

.. cmake:command:: exclude_all_but_from_headercheck

  .. dune:internal::

  Remove all ``*.hh`` files in the current directory from the global
  headercheck list except the specified ones.

.. cmake:command:: finalize_headercheck

  .. dune:internal::

  Create the individual headercheck compilation targets for all headers that
  remain in the global headercheck list.