Error 255 in making HDL project on Windows

Hi,

I keep getting a make error 255 when I try to make a HDL project on Windows using GNUwin:

[...]\projects\adrv9364z7020\ccbob_lvds>make
lib was unexpected at this time.
make: *** [../../scripts/project-xilinx.mk:60: lib] Error 255

It seems that Error 255 means that the make command shell is not able to find a command for a particular rule.
I added the following environment variables (PATH):

C:\Xilinx\SDK\2018.3\gnuwin\bin
C:\Xilinx\Vivado\2018.3\bin
C:\Xilinx\Vivado\2018.3\lib\win64.o

C:\Xilinx\SDK\2018.3\bin
C:\Xilinx\SDK\2018.3\gnu\microblaze\nt\bin
C:\Xilinx\SDK\2018.3\gnu\armr5\nt\gcc-arm-none-eabi\bin
C:\Xilinx\SDK\2018.3\gnu\microblaze\linux_toolchain\nt64_le\bin
C:\Xilinx\SDK\2018.3\gnu\aarch32\nt\gcc-arm-none-eabi\bin

The suggestions on the wiki (https://wiki.analog.com/resources/fpga/docs/build) to verify the environment setup by executing the "which ... " commands all seem to be showing that it should work.
Do you have any suggestions on how to make this work?

Thanks in advance!