For those who want to tinker, see my packages. The library came across OK but gphoto itself uses a newer debhelper, so I just plucked the binary itself into the repo. If you want to use this with libferris, then expand the additional libraries into /usr/local/lib/ferris/plugins/context on the device.
I found that once USB mode was set to host, I could see the camera with gphoto but as reported in the past, there were frequent crashes. This is really unfortunate as all the blocks where in place for the command I was chasing:
# ferriscp -av \
Most of the time using gphoto locks everything and about 5-10 seconds later the device restarts. I might have to hunt for a newer kernel for diablo... or wait until I have gphoto support on an n9 (nn?), a P+S wifi camera, and a decent data plan...