Relevant guards can be found in ef5579dc86/modules/features2d/src/kaze/AKAZEConfig.h (L8) and ef5579dc86/modules/ml/include/opencv2/ml.hpp (L44)
ef5579dc86/modules/features2d/src/kaze/AKAZEConfig.h (L8)
ef5579dc86/modules/ml/include/opencv2/ml.hpp (L44)