First off the BSP document does not list g++ as one of the required installs, but it is required.
I have tried several times to be able to build the 8.0 firmware, and I have not been able to do so. Every time seems to end with the same error:
ERROR: Nothing PROVIDES 'image-full'
I have tried this on 12.04 and on 13.10 versions of Unbuntu. Both fail. Attached is the output from running on 12.04 on a virtual machine.