After a succesful configure, make exits with snipped
gclosure.c:29:17: fatal error: ffi.h: No such file or directory
compilation terminated.
Check your GCC version and note this entry in the Debian Bug Archive: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=523869
It was the final solution to my particular issue (it looked exactly like what you report, but couldn't be solved with the solution above)... my problem had nothing to do with LIBFFI at all.