This special file[1] can contain the defines like QTI_BSP and QCOM_BSP
which then modifies the API/ABI of the hwcomposer[2].
This defines are required in order to make kwin_wayland work on !nexus
QCOM devices and also possibly other special devices.
[1] https://github.com/Halium/android-headers/blob/master/android-config.h
[2] https://github.com/Halium/android-headers/blob/halium-7.1/hardware/hwcomposer.h#L290