我正在尝试为CTS执行构建webkittestcases.apk，但是在构建apk时出现以下错误
out/build-aosp_arm-cts_tests_tests_webkit_Android.mk.ninja is missing, regenerating...
PRODUCT_COPY_FILES device/.../..:root/stab ignored.
PRODUCT_COPY_FILES device/..../.early:root/stab.early ignored.
device/qcom/...../vendor_bootjars.mk:7: error: cannot assign to readonly variable: PRODUCT_BOOT_JARS
08:59:21 ckati failed with: exit status 1
我的AOSP android版本是8.1