[xorcist]

That's ... how autoconf works?

If you explicitly set the enable-landlock flag, configure will fail when the feature doesn't compile.

[snnn]

A cmake option only has two values: ON or OFF. There is no unset. Because it is a boolean.

See: https://cmake.org/cmake/help/latest/command/option.html

[account42]

This is not actually true, you can check if variables have been defined in CMake.

[xorcist]

Right, but the boolean is set by an autoconf script, is it not?