[Openflipper] Disable plugin when building?

Hello, When building OpenFlipper, how can I disable a plugin without renaming its directory? I would expect some option passed to openflipper_plugin() in the plugin's CMakeLists.txt but could not find any documentation for that. Looking at common.cmake it, say, DISABLE_PLUGIN_SimplePlugin is defined, then it will be disabled. But I cannot figure out where and how to define DISABLE_PLUGIN_SimplePlugin. Sorry if this is too trivial. I do not know CMake well enough, Best regards, Waqar