Currently, all subdirectories under libs/XXX/include are recursively added to the include search paths.
This can sometimes cause problems.
For example, when using ofxOpenCV together with flann-lib, conflicts can occur because files with the same name exist in multiple include search paths.
In general, OpenCV expects headers to be included using paths relative to the include root, such as:
#include <opencv2/XXX.hpp>
(Although the current ofxOpenCV setup seems more complex, possibly due to OpenCV 4 support.)
Other libraries are typically designed in the same way.
Therefore, I think it would be better not to recursively add all subdirectories under libs/XXX/include by default.
If additional include paths are required, they could instead be explicitly specified in addon_config.mk.
Would this approach make sense?