ArrowOS Pix3XL compile error

hardware/qcom/sdm845/display/liblight/lights.c:33:10: fatal error: 'linux/msm_mdp.h' file not found
hardware/qcom/sdm845/display/libhistogram/histogram_collector.cpp:35:10: fatal error: 'drm/msm_drm_pp.h' file not found

You need to set:
TARGET_SPECIFIC_HEADER_PATH := device/semc/<device>/include

and populate this with include files you need, e.g:
include/linux/msm_mdp.h

In device BoardConfig.mk
TARGET_SPECIFIC_HEADER_PATH := $(PLATFORM_PATH)/include