mark_as_advanced
----------------

Mark cmake cached variables as advanced.

.. code-block:: cmake

  mark_as_advanced([CLEAR|FORCE] <var1> ...)

Sets the advanced/non-advanced state of the named
cached variables.

An advanced variable will not be displayed in any
of the cmake GUIs unless the ``show advanced`` option is on.
In script mode, the advanced/non-advanced state has no effect.

If the keyword ``CLEAR`` is given
then advanced variables are changed back to unadvanced.
If the keyword ``FORCE`` is given
then the variables are made advanced.
If neither ``FORCE`` nor ``CLEAR`` is specified,
new values will be marked as advanced, but if a
variable already has an advanced/non-advanced state,
it will not be changed.
