Provide a boolean option that the user can optionally select.

option(<variable> "<help_text>" [value])

If no initial <value> is provided, boolean OFF is the default value. If <variable> is already set as a normal or cache variable, then the command does nothing (see policy CMP0077).

For options that depend on the values of other options, see the module help for CMakeDependentOption.

In CMake project mode, a boolean cache variable is created with the option value. In CMake script mode, a boolean variable is set with the option value.