DuneProvidePybind11
-------------------

Helpers for providing pybind11 to DUNE Python extension targets.

.. cmake:variable:: DUNE_USE_SYSTEM_PYBIND11

  Use an external pybind11 installation instead of the vendored headers shipped
  with ``dune-common``.

  When this option is enabled, :cmake:command:`dune_provide_pybind11()` first
  tries :cmake:command:`find_package(pybind11 CONFIG)`. If that fails, it
  downloads pybind11 and creates an imported compatibility target for it.

.. cmake:command:: dune_provide_pybind11

  Ensure that the given target can use pybind11.

  Depending on :cmake:variable:`DUNE_USE_SYSTEM_PYBIND11`, this either links the
  target against an external or downloaded ``pybind11::module`` target, or adds
  the vendored include directory from ``dune-common`` directly.

  .. code-block:: cmake

    dune_provide_pybind11(<target>)

  ``target``
    Existing target that should be configured for pybind11 usage.