Haven't done much for a few days as I have been busy at work since my boss is on holiday.
I finally managed to get gnumeric to appear to build ok with gb support. However, when I ran the demo program (enter =demo() into a cell) it segfaulted. I havent managed to track it down yet, although I had a quick look at it gdb. I dont have too much experience of debuggers but hopefully a bit more work and I may at least be able to tell why it crashes.