[Error] Building Android Pie

Good afternoon. I ask for your help in solving one problem.
I decided to build Android 9 (pie) according to this documentation.
I followed the instructions and downloaded the source code for Android 9:

repo init -u https://github.com/khadas/android_manifest.git -b khadas-vims-pie

Next, when I got to the Android build I got the following problem:

I ask for help in solving the problem

The problem has been resolved. In device.mk, add a backslash to the end of line 44.

device/khadas/$(PRODUCT_DIR)/files/filteredid.cfg:$(TARGET_COPY_OUT_VENDOR)/etc/filteredid.cfg \
device/khadas/$(PRODUCT_DIR)/files/remote.cfg:$(TARGET_COPY_OUT_VENDOR)/etc/remote.cfg \