Custom lib outside-the-tree that depends on mbedtls - Build fails

[naNEQ]

I'm working on integrating a custom library to our project, exactly the way it is described in the example application repo, where a custom library is added outside the Zephyr tree. It all works fine up to the point that I need to use some functions from a Zephyr module, in particular mbedtls.

But then the problem is that I get a build error because the header files from mbedtls I want to include are not found by the building system.

I suspect this is because in the CMakeLists file of Zephyr, the lib folder, where my custom library is placed, is processed before the modules folder, where mbedtls is present. Therefore, the mbedtls header files are not yet added and are not found when they are needed by the library.

Is there anyone that has encountered similar challenges to give me some advice?