Reviving an old thread... Recall that David Pirotte had trouble linking libguile-2.0.so because -lffi was not included in the link command, despite the fact that `pkg-config --libs libffi' did the right thing.
I ran into the same problem trying to build guile on gNewSense/mipsel. In my case, the problem was that I had set PKG_CONFIG=true while running configure. I did this because it was recommended by the README in the section on setting the BDW_GC_* variables. Perhaps that was David's problem as well? Mark